Question

They live on a busy road ........................................ a lot of noise from the traffic.

• A. It must be
• B. it must have
• C. there must have
• D. there must be

Hint:

For present deductions about existence, prefer \textbf{there must be + noun}. Use {there must have been} only for past time.

Answer 1

The Correct Option is D

Step 1 (Meaning): The sentence states a logical conclusion about {existence} of noise on a busy road. We therefore need the existential pattern {there is/are} with the modal of deduction {must}.
Step 2 (Form): The correct present-time deduction is {there must be + noun} (“there must be a lot of noise”).
Step 3 (Reject others): (a) “It must be a lot of noise” is ungrammatical because “it” cannot stand for a plural/uncountable entity in this way; the existential “there” is required. (b) “must have” expresses past deduction, not needed here. (c) “there must have” needs a past participle ({been}), which is missing and would still shift the time to the past ({there must have been}). Hence (d).