Question

You __________ speak in the library.

A. must not

B. dare not

C. need not

D. could not

Answer 1

Answer:

must not is the correct option

Answer 2

You must not speak in the library.(option A)

• Here, the word 'must not' is an auxiliary verb that expresses the ideas like necessity or prohibition.
• The other provided options do not fit into the sentence as they do not provide the exact meaning or convey the exact meaning of the given sentence when used.
• 'must not' tells us that something is strictly prohibited whereas other options do not convey the message of strictly prohibited when used in the sentence. Therefore, option A is the correct answer.