Question

Fill in the blank with the most appropriate word.
He is getting fatter and fatter. He ________ eating too much.

• A. must be
• B. can be
• C. may
• D. might

Answer 1

The correct option is A must be

The context refers to a person gaining weight. From this it can be deduced that his diet is responsible for such weight gain. Hence, "must be" in option A is correct as it indicates a deduction of what must follow in a particular case.
"Can be" implies ability or permission. This is unsuited to the context.
"May" indicates possibility or permission. This is incorrect in the given context as it refers to extreme weight gain which cannot possibly have any other apparent reason.
"Might" indicates a slight possibility. As the context implies that the weight gain is exponential, it must follow that the diet is responsible.
Thus, option A is correct.