Explanation
A workflow action is a link that appears when you click an event field value in your search results1. A workflow action can open a web page or run another search based on the field value1. There are two types of workflow actions: GET and POST1. A GET workflow action appends the field value to the end of a URI and opens it in a web browser1. A POST workflow action sends the field value as part of an HTTP request to a web server1. You can configure a workflow action to open a web page in either the same window or a new window1. Therefore, option D is correct, while options A, B and C are incorrect.

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

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

Explanation
During the validation step of the Field Extractor workflow, you can remove values that aren't a match for the field you want to define2. The validation step allows you to review and edit the values that have been extracted by the FX and make sure they are correct and consistent2. You can remove values that aren't a match by clicking on them and selecting Remove Value from the menu2. This will exclude them from your field extraction and update the regular expression accordingly2. Therefore, option A is correct, while options B and C are incorrect because they are not actions that you can perform during the validation step of the Field Extractor workflow.