To create a tag, the user must have the tag capability associated with their user role. The tag capability allows
the user to create, edit, and delete tags. The user does not need to identify a field:value pair, have the Power
role, or be able to edit the sourcetype the tag applies to.ReferencesSee Define and manage tags in Settings and
[About capabilities] in the Splunk Documentation.

Explanation
https://docs.splunk.com/Documentation/Splunk/8.1.0/SearchReference/Chart
https://docs.splunk.com/Documentation/Splunk/8.1.0/SearchReference/Stats

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

Explanation
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