Explanation
The correct syntax to find events associated with a tag is A. tag:<field>=<value>.
A tag is a way to add descriptive keywords to events based on field values. Tags can be used to filter and group events by common characteristics, such as source type, host, severity, or category1.
To search for events that have a specific tag, you need to use the tag field with the name of the field and the value of the tag as the arguments. The syntax for this is:
tag:<field>=<value>
For example, if you want to search for events that have the tag "error" for the status field, you can use the following syntax:
tag:status=error
This will return only the events that have the status field value tagged as "error".
The other options are not correct because they use different syntax or fields that are not related to tags. These options are:
B: tags=<value>: This option uses the tags field, which is a multivalue field that contains all the tags associated with an event. However, this field is not searchable by default and requires additional configuration to enable it1.
C: tags:<field>=<value>: This option uses the tags field with a colon instead of an equal sign, which is not valid syntax for searching with fields.
D: tag=<value>: This option uses the tag field without specifying the name of the field, which is not valid syntax for searching with tags.
References:
About tags
Search with tags