Explanation
The command sourcetype=access_combined | transaction JSESSIONID does three things:
It filters the events by the sourcetype access_combined, which is a predefined sourcetype for Apache web server logs.
It groups the events by the field JSESSIONID, which is a unique identifier for each user session.
It creates a single event from each group of events that share the same JSESSIONID value. This single event will have some additional fields created by the transaction command, such as duration, eventcount, and startime.
Therefore, the statements B, C, and D are true.

The correct syntax to find events associated with a tag in Splunk istag=<value>1. So, the correct answer isD.
tag=<value>.This syntax allows you to annotate specified fields in your search results with tags1.
In Splunk, tags are a type of knowledge object that you can use to add meaningful aliases to field values in
your data1. For example, if you have a field calledstatus_codein your data,you might have different status
codes like 200, 404, 500, etc. You can create tags for these status codes likesuccessfor 200,not_foundfor 404,
andserver_errorfor 500.Then, you can use thetagcommand in your searches to find events associated with
these tags1.
Here is an example of how you can use thetagcommand in a search:
index=main sourcetype=access_combined | tag status_code
In this search, thetagcommand annotates thestatus_codefield in the search results with the corresponding
tags.If you have tagged the status code 200 withsuccess, the status code 404 withnot_found, and the status
code 500 withserver_error, the search results will include these tags1.
You can also use thetagcommand with a specific tag value to find events associated with that tag. For
example, the following search finds all events where the status code is tagged withsuccess:
index=main sourcetype=access_combined | tag status_code | search tag::status_code=success
In this search, thetagcommand annotates thestatus_codefield with the corresponding tags, and
thesearchcommand filters the results to include only events where thestatus_codefield is tagged withsuccess1.

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

Explanation/Reference:

Explanation/Reference: https://docs.splunk.com/Documentation/CIM/4.15.0/User/UsetheCIMtonormalizedataatsearchtime