Поставьте правильный модальный глагол. All passengers _________ smoke on board the plane....

Question

Поставьте правильный модальный глагол.
All passengers _________ smoke on board the plane.
1) must;
2) can;
3) must not;
4) cannot.

Answer 1

3)all passengers mustn't smoke on board the plane

Answer 2

All passengers must not