In Splunk, data sets used in the Pivot tool are derived from data models. The Pivot tool allows users to create reports and visualizations based on the structured information available in data models.
Reference:
Splunk Docs - Pivot tool

https://docs.splunk.com/Documentation/Splunk/8.0.2/Knowledge/SetupaGETworkflowaction Define a GET workflow action Steps Navigate to Settings > Fields > Workflow Actions.
Click New to open up a new workflow action form.
Define a Label for the action.
The Label field enables you to define the text that is displayed in either the field or event workflow menu. Labels can be static or include the value of relevant fields.
Determine whether the workflow action applies to specific fields or event types in your data.
Use Apply only to the following fields to identify one or more fields. When you identify fields, the workflow action only appears for events that have those fields, either in their event menu or field menus. If you leave it blank or enter an asterisk the action appears in menus for all fields.
Use Apply only to the following event types to identify one or more event types. If you identify an event type, the workflow action only appears in the event menus for events that belong to the event type.
For Show action in determine whether you want the action to appear in the Event menu, the Fields menus, or Both.
Set Action type to link.
In URI provide a URI for the location of the external resource that you want to send your field values to.
Similar to the Label setting, when you declare the value of a field, you use the name of the field enclosed by dollar signs.
Variables passed in GET actions via URIs are automatically URL encoded during transmission. This means you can include values that have spaces between words or punctuation characters.
Under Open link in, determine whether the workflow action displays in the current window or if it opens the link in a new window.
Set the Link method to get.
Click Save to save your workflow action definition.

The correct answer is B. Event category tags. This is because the CIM add-on contains a collection of preconfigured data models that you can apply to your data at search time. Each data model in the CIM consists of a set of field names and tags that define the least common denominator of a domain of interest. Event category tags are used to classify events into high-level categories, such as authentication, network traffic, or web activity. You can use these tags to filter and analyze events based on their category. You can learn more about event category tags from the Splunk documentation12. The other options are incorrect because they are not included with the CIM add-on. Search macros are reusable pieces of search syntax that you can invoke from other searches. They are not specific to the CIM add-on, although some Splunk apps may provide their own search macros. Workflow actions are custom links or scripts that you can run on specific fields or events. They are also not specific to the CIM add-on, although some Splunk apps may provide their own workflow actions. tsidx files are index files that store the terms and pointers to the raw data in Splunk buckets. They are part of the Splunk indexing process and have nothing to do with the CIM add-on.

Reference:
One of the statements that would help a user choose between the transaction and stats commands is that there is a 1000 event limitation with the transaction command3. The transaction command is used to group events that share a common value for one or more fields into transactions3. The transaction command has a default limit of 1000 events per transaction, which means that it will not group more than 1000 events into a single transaction3. This limit can be changed by using the maxevents parameter, but it can affect the performance and memory usage of Splunk3. Therefore, option C is correct, while options A, B and D are incorrect because they are not statements that would help a user choose between the transaction and stats commands.