Normalize your data for each of these fields using a combination of field aliases, field extractions, and lookups.
https://docs.splunk.com/Documentation/CIM/4.15.0/User/UsetheCIMtonormalizedataatsearchtime

The correct answer is B. Reusable pieces of search processing language.
The explanation is as follows:
Search macros are knowledge objects that allow you to insert chunks of SPL into other searches12.
Search macros can be any part of a search, such as an eval statement or a search term, and do not need to be a complete command12.
You can also specify whether the macro field takes any arguments and define validation expressions for them12.
Search macros can help you make your SPL searches shorter and easier to understand3.
To use a search macro in a search string, you need to put a backtick character () before and after the macro name[^1^][1]. For example, mymacro`.

The transaction command is a Splunk command that finds transactions based on events that meet various constraints .
Transactions are made up of the raw text (the _raw field) of each member, the time and date fields of the earliest member, as well as the union of all other fields of each member .
The transaction command groups events together by matching one or more fields that have the same value across the events . For example, | transaction clientip will group events that have the same value in the clientip field.