February 28 March 7 March 14 March 21
I gave my students this multiple choice question: On February 21, a student observes that the Moon cannot be seen in the clear night sky. On what date will the student not be able to see the Moon again in the clear night sky?

Only one answer is correct among these 4 choices:
- February 28
- March 7
- March 14
- March 21

Could you tell me which one is correct?

March 21