The ruling on saying “Allah and His Messenger know best” after the death of the Prophet (peace and blessings be upon him)

Question:
If the question is asked after the death of the Prophet (peace and blessings be upon him), should the one asked say “Allah and His Messenger know best” if he does not know, or should he say only “Allah knows best”?

Answer:
The scholars drew attention to this, saying that this is during the life of the Messenger, but after his death, one says “Allah knows best.”