Question

Fill in the blank with a suitable modal:

When people are driving, they ______ keep their eyes on the road.

• A. will
• B. can
• C. must
• D. should

Answer 1

The correct option is C must

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.

According to the meaning of the sentence it expects an extreme obligation

Option C is the correct answer because it expresses extreme obligation

Whereas option A expresses certainty in future action

option D expresses an advice regarding what is correct.

option B expresses ability