The correct answer is D. eval.
A calculated field is a field that is added to events at search time by using an eval expression. A calculated field can use the values of two or more fields that are already present in the events to perform calculations. A calculated field can be defined with Splunk Web or in the props.conf file. They can be used in searches, reports, dashboards, and data models like any other extracted field1.
A calculated field is a shortcut for performing repetitive, long, or complex transformations using the eval command. The eval command is used to create or modify fields by using expressions. The eval command can perform mathematical, string, date and time, comparison, logical, and other operations on fields or values2.
For example, if you want to create a new field named total that is the sum of two fields named price and tax, you can use the eval command as follows:
| eval total=price+tax
However, if you want to use this new field in multiple searches, reports, or dashboards, you can create a calculated field instead of writing the eval command every time. To create a calculated field with Splunk Web, you need to go to Settings > Fields > Calculated Fields and enter the name of the new field (total), the name of the sourcetype (sales), and the eval expression (price+tax). This will create a calculated field named total that will be added to all events with the sourcetype sales at search time. You can then use the total field like any other extracted field without writing the eval expression1.
The other options are not correct because they are not related to calculated fields. These options are:
* A. transaction: This command is used to group events that share some common values into a single record, called a transaction. A transaction can span multiple events and multiple sources, and can be useful for correlating events that are related but not contiguous3.
* B. lookup: This command is used to enrich events with additional fields from an external source, such as a CSV file or a database. A lookup can add fields to events based on the values of existing fields, such as host, source, sourcetype, or any other extracted field.
* C. stats: This command is used to calculate summary statistics on the fields in the search results, such as count, sum, average, etc. It can be used to group and aggregate data by one or more fields.
References:
* About calculated fields
* eval command overview
* transaction command overview
* [lookup command overview]
* [stats command overview]

The correct answer is C. Creates reports without using SPL. This is because the Pivot tool is a feature of Splunk that allows you to report on a specific data set without using the Splunk Search Processing Language (SPL). You can use a drag-and-drop interface to design and generate pivots that present different aspects of your data in the form of tables, charts, and other visualizations. You can learn more about the Pivot tool from the Splunk documentation1 or watch a video tutorial2. The other options are incorrect because they do not describe the features of the Pivot tool. The Pivot tool requires data models and datasets to define the data that you want to work with. Data models and datasets are designed by the knowledge managers in your organization. You can learn more about data models and datasets from the Splunk documentation3. The Pivot tool does not create lookups, which are tables that match field values to other field values. You can create lookups using SPL or the Lookup Editor. You can learn more about lookups from the Splunk documentation.

Splunk alerts can be based on searches that run in real-time or on a regular schedule3. An alert is a way to monitor your data and get notified when certain conditions are met3. You can create an alert by specifying a search and a triggering condition3. You can also specify how often you want to run the search and how you want to receive the alert notifications3. You can run the alert search in real-time, which means that it continuously monitors your data as it streams into Splunk3. Alternatively, you can run the alert search on a regular schedule, which means that it runs at fixed intervals such as every hour or every day3. Therefore, options A and B are correct, while option C is incorrect because it is not a way to run an alert search.

Reference: https://docs.splunk.com/Documentation/Splunk/8.0.3/Knowledge/FXSelectMethodstep The Field Extractor (FX) is a tool that helps you extract fields from your data using delimiters or regular expressions. Delimiters are characters or strings that separate fields in your data. The FX can detect some common delimiters automatically, such as pipes (|), spaces ( ), commas (,), semicolons (;), etc. The FX cannot detect tabs (\t) as delimiters automatically, but you can specify them manually in the FX interface.

The search string below returns events from the data model named Application_State.
| datamodel Application_State All_Application_State search
The search string does the following:
It uses the datamodel command to access a data model in Splunk. The datamodel command takes two arguments: the name of the data model and the name of the dataset within the data model.
It specifies the name of the data model as Application_State. This is a predefined data model in Splunk that contains information about web applications.
It specifies the name of the dataset as All_Application_State. This is a root dataset in the data model that contains all events from all child datasets.
It uses the search command to filter and transform the events from the dataset. The search command can use any search criteria or command to modify the results.
Therefore, the search string returns events from the data model named Application_State.