Answer:
B. Populous
Explanation:
The best option that completes this sentence is the word 'populous'.
Did you know Hong Kong is one of the world's most populous cities?
To complete this sentence we needed a word that modifies the noun 'cities', so we needed an adjective.
Option A is wrong because it is misspelled.
Option C is wrong because it is a noun. To put two nouns together doesn't make any sense to the information of the sentence.
Option B is correct.
Populous (adjective) - full of residents or inhabitants, as a region; heavily populated. This word is completely suitable for our sentence as it finishes its complete thought.
I hope it helped you :)
