https://docs.splunk.com/Documentation/Splunk/8.1.0/SearchReference/ConversionFunctions#tostring.28X.2CY.29 The tostring function in the eval command converts a numeric value to a string value. It can take an optional second argument that specifies the format of the string value. Some of the possible formats are:
hex: converts the numeric value to a hexadecimal string.
commas: adds commas to separate thousands in the numeric value.
duration: converts the numeric value to a human-readable duration string, such as “2h 3m 4s”.
Therefore, the formats A, B, and D can be used with the tostring function.

Reference:
https://docs.splunk.com/Documentation/PCI/4.1.0/Install/PrivilegedUserActivity

Reference:https://docs.splunk.com/Documentation/Splunk/8.0.3/Knowledge/SetupaPOSTworkflowaction

https://docs.splunk.com/Documentation/Splunk/latest/SearchReference/CommonEvalFunctions

Reference:https://docs.splunk.com/Documentation/SplunkCloud/8.0.2003/Search/Usethesearchcommand

The statement that fields extracted using the Field Extractor persist as knowledge objects is true. The Field Extractor (FX) is a graphical tool that allows you to extract fields from raw events using regular expressions or delimiters. The fields extracted by the FX are saved as knowledge objects that can be used in future searches or shared with other users.

Explanation
The correct answer is A. chart, timechart, stats, eventstats.
Transforming commands are commands that change the format of the search results into a table or a chart.
They can be used to perform statistical calculations, create visualizations, or manipulate data in various ways1.
Transactions are groups of events that share some common values and are related in some way. Transactions can be defined by using the transaction command or by creating a transaction type in the transactiontypes.conf file2.
Some transforming commands can be used with transactions to create tables or charts based on the transaction fields. These commands include:
chart: This command creates a table or a chart that shows the relationship between two or more fields. It can be used to aggregate values, count occurrences, or calculate statistics3.
timechart: This command creates a table or a chart that shows how a field changes over time. It can be used to plot trends, patterns, or outliers4.
stats: This command calculates summary statistics on the fields in the search results, such as count, sum, average, etc. It can be used to group and aggregate data by one or more fields5.
eventstats: This command calculates summary statistics on the fields in the search results, similar to stats, but it also adds the results to each event as new fields. It can be used to compare events with the overall statistics.
These commands can be applied to transactions by using the transaction fields as arguments. For example, if you have a transaction type named “login” that groups events based on the user field and has fields such as duration and eventcount, you can use the following commands with transactions:
| chart count by user : This command creates a table or a chart that shows how many transactions each user has.
| timechart span=1h avg(duration) by user : This command creates a table or a chart that shows the average duration of transactions for each user per hour.
| stats sum(eventcount) as total_events by user : This command creates a table that shows the total number of events for each user across all transactions.
| eventstats avg(duration) as avg_duration : This command adds a new field named avg_duration to each transaction that shows the average duration of all transactions.
The other options are not valid because they include commands that are not transforming commands or cannot be used with transactions. These commands are:
diff: This command compares two search results and shows the differences between them. It is not a transforming command and it does not work with transactions.
datamodel: This command retrieves data from a data model, which is a way to organize and categorize data in Splunk. It is not a transforming command and it does not work with transactions.
pivot: This command creates a pivot report, which is a way to analyze data from a data model using a graphical interface. It is not a transforming command and it does not work with transactions.
References:
About transforming commands
About transactions
chart command overview
timechart command overview
stats command overview
[eventstats command overview]
[diff command overview]
[datamodel command overview]
[pivot command overview]

Reference:https://docs.splunk.com/Documentation/Splunk/8.0.3/Knowledge/Usesearchmacros

To use a search macro in a search string, you need to place a back tick character (`) before and after the macro name1. You also need to use the same number of arguments as defined in the macro2. The macro weekly sales (2) has two arguments: Price and AmountSold. Therefore, you need to provide two values for these arguments when you call the macro.
The option A is incorrect because it uses parentheses instead of back ticks around the macro name. The option B is incorrect because it uses underscores instead of spaces in the macro name. The option D is incorrect because it uses spaces instead of commas to separate the argument values.

Reference:
Data models are collections of datasets that represent your data in a structured and hierarchical way. Data models define how your data is organized into objects and fields. Data models can be composed of one or more of the following datasets:
Events datasets: These are the base datasets that represent raw events in Splunk. Events datasets can be filtered by constraints, such as search terms, sourcetypes, indexes, etc.
Search datasets: These are derived datasets that represent the results of a search on events or other datasets. Search datasets can use any search command, such as stats, eval, rex, etc., to transform the data.
Transaction datasets: These are derived datasets that represent groups of events that are related by fields, time, or both. Transaction datasets can use the transaction command or event types with transactiontype=true to create transactions.

Reference:
https://answers.splunk.com/answers/103/transaction-vs-stats-commands.html