Reference: https://docs.splunk.com/Documentation/Splunk/8.0.3/Pivot/IntroductiontoPivot A pivot is a tool that allows you to create reports and dashboards using data models without writing any SPL commands2. You can use pivots to explore, filter, split and visualize your data using a graphical interface2. Pivots are designed for users who want to analyze and report on their data without having to learn the SPL syntax or the underlying structure of the data2. Therefore, option A is correct, while options B, C and D are incorrect because they are not the typical group of users who would use pivots.

The correct answer is C. By enclosing the macro name in backtick characters (`).
A macro is a way to reuse a piece of SPL code in different searches. A macro can take arguments, which are variables that can be replaced by different values when the macro is called. A macro can also contain another macro within it, which is called a nested macro1.
To reference a macro in a search, you need to enclose the macro name in backtick characters (). For example, if you have a macro named my_macro` that takes one argument, you can reference it in a search by using the following syntax:
| my_macro(argument) | ...
This will replace the macro name and argument with the SPL code contained in the macro definition. For example, if the macro definition is:
[my_macro(argument)] search sourcetype=$argument$
And you reference it in a search with:
index=main | my_macro(web) | stats count by host
This will expand the macro and run the following SPL code:
index=main | search sourcetype=web | stats count by host
References:
* Use search macros in searches

The transaction command in Splunk groups events based on common fields and creates a single transaction event. The timestamp assigned to the transaction is the timestamp of the earliest event in the transaction. This ensures that the transaction reflects the actual start time of the related events rather than the time the transaction is created or ended.
Reference:
Splunk Power User Study Guide, Chapter on Transaction Command
Splunk Documentation: transaction Command
"The timestamp of the resulting transaction is the timestamp of the earliest event in the transaction."