If someone posted an anonymous comment on one of the protestor$$s pages, which Rita was reviewing, that threatened the life of government workers, can the Department of Justice compel the social media app to reveal the user?

No$,$ because the Fourth Amendment protects the anonymity of social media users.

No$,$ because it was a message to another user and not to the public at large.

Yes, because there is no reasonable expectation of privacy in content posted by a user.

Yes, because there is an imminent threat of harm to government workers.