For questions about protected questions. Protected questions are only able to be answered by users who have earned at least 10 reputation on the site

Protected questions are questions that require a minimum of 10 reputation to answer. This ignores the association bonus, so you must have at least 10 reputation earned on CGCC.

Questions can be protected in the following ways:

Additionally, diamond moderators and 15k+ users can unprotect any protected question at will.

See the site policy on when to protect questions.