Question

Fill a suitable option as per the situation given:

(The doorbell rings) I wonder who that is. It ________ Mary. She's still at work at this time.

• A. won't be
• B. couldn't be
• C. can't be
• D. mustn't be

Answer 1

Answer: (C)

Modal Verbs show us the attitude of the speaker to what is being said or done. The term "modal" means expressing mood and mood is a way to express the attitude of the speaker.

Option B is the correct answer because it expresses less possibility, as Mary is at work.

Whereas option A expresses same as option B but it is in past tense therefore it is not applicable in the sentence.;

option C expresses its condition in future as a result it is not applicable in the give sentence;

option D expresses what is not supposed to be done with extreme obligation , therefore it is incorrect as well.