Choose the most appropriate Modal from the given options and fill in the blank :
This answer can't be right; It ________ be wrong.
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Must
Complete sentence: This answer can't be right; it must be wrong. The first half says "This answer can't be right", so the second half states the certain conclusion: "It must be wrong."
| Option | Meaning and use | Example |
|---|---|---|
| (1) May | only possibility. After the certain "can't be right" the speaker is not merely guessing. | It may rain this evening. |
| (2) Can | Positive "can" shows ability or general possibility. It is not used for a firm conclusion about one case. | He can lift heavy boxes. |
| (3) Ought to | duty or what is expected. "It ought to be wrong" makes no sense. | You ought to respect your elders. |
| (4) Must (answer) | Must expresses that the speaker is sure something is true, from the evidence. Can't is its negative partner: the speaker is sure something is not true. | The lights are off; they must be asleep. |