Which of the following is true of a namespace?

The correct answer is A because the namespace is a type of token filter. The namespace is a parameter that can be used to filter the tokens returned by the REST API. The namespace consists of the user and the app context, which determine the scope and visibility of the knowledge objects in Splunk. Option B is incorrect because the namespace can include a wildcard (*) for the app attribute, which means it will return tokens from all apps. Option C is incorrect because the namespace does not filter the knowledge objects returned by the REST API, but rather the tokens that reference them. Option D is incorrect because the namespace does filter the tokens returned by the REST API, based on the user and app context. You can find more information about the namespace and the token filter in the Splunk REST API Reference Manual.