Question

Tokyo is one of the mostly populated cities in the world.

• A. thickly populated city in
• B. thickly populated city of
• C. most populated cities in
• D. No correction required

Hint:

"Mostly" = adverb (to a large extent). "Most populated" = superlative degree, correct for comparisons.

Answer 1

The Correct Option is C

"Mostly populated" is incorrect. The intended meaning is "one of the most populated cities." Thus, option (c) is the correct substitution. \[ \boxed{\text{most populated cities in}} \]

Answer 2

Use the "one of the ___" structural rule: this construction always requires a plural noun and a superlative adjective, so test each option against that rule first.

1. Option A: "one of the thickly populated city in" uses a singular noun ("city"), which directly violates the "one of the ___" rule requiring a plural noun.
2. Option B: has the same singular-noun problem as option A, and additionally uses "of" instead of the correct preposition "in."
3. Option C: "one of the most populated cities in the world" correctly uses the plural noun "cities," the superlative "most," and the standard preposition "in."
4. Option D: "mostly populated" is an adverb misused as an intensifier before "populated," which is not standard usage, so the original cannot stand.

Only option C satisfies the plural-noun-plus-superlative requirement of the construction.

Hence, the correct answer is most populated cities in.