Answer: C) Must, have to.
Explanation for this question is being written.
Answer: A) To do.
Answer: B) Must
Answer: C) Objective obligation.
Answer: C) Mustn't
Answer: A) Mustn't
Answer: A) Must
Answer: B) Musn't
Answer: B) Mustn't
Answer: D) Musn't / must.
Answer: D) Mustn't
Answer: D) Press photographers mustn't take photographs backstage.
Answer: C) Must
Answer: A) You must stop.
Answer: B) You must clean the mess!
Answer: D) Must
Answer: B) False, he can never.
Answer: C) Must be quiet.
Answer: B) Don't have to.
Answer: A) We must finish it now.
Answer: B) Have
Answer: A) Had to sit / was able to complete.
Answer: B) False
Answer: A) He mustn't make a lot of noise in the museum.