[Reference: https://docs.splunk.com/Documentation/Splunk/8.0.3/Knowledge/TagandaliasfieldvaluesinSplunkWeb, A tag is a descriptive label that you can apply to one or more fields or field values in your events2. You can use tags to simplify your searches by replacing long or complex field names or values with short and simple tags2. To search for a tag associated with a value on a specific field, you can use the following syntax: tag::=2. For example, tag::status=error will search for events where the status field has a tag named error. Therefore, option D is correct, while options A, B and C are incorrect because they do not follow the correct syntax for searching tags., , ]