Question

Fill in the blank with the most suitable option:
Since you have been working for hours, you ______________ tried.

• A. Must be
• B. Can't be
• C. Must have been
• D. Might have been

Answer 1

The correct option is A Must be

The correct answer is Option A.

MUST BE is used to state something with certainty.

In the given sentence, it is certain that the person is tired because he has been working for hours.

Thus MUST BE is the correct answer.

The remaining options are incorrect because:

CAN'T BE expresses inability.

MUST HAVE BEEN is the present perfect tense, whereas the given sentence is in the present tense.

MIGHT HAVE BEEN expresses possibility.