Question

Fill in the blank with a suitable adjective clause:
People ________________ are often the most observant. [Advanced]

• A. eating too much
• B. sleeping all day long
• C. who don't speak much
• D. none of the above

Answer 1

The correct option is C who don't speak much

An adjective clause is a group of words that contain a subject and a verb, and it functions as an adjective that modifies a noun or a pronoun. Adjective clauses usually begin with relative pronouns such as who, whom, whose or a relative adverb like when, where and so on.
Option C is correct as it is an adjective clause containing a subject 'who' (which is a relative pronoun), a verb 'don't speak' and modifies the noun "people".
Option A is incorrect because it is a phrase, not a clause, it does not have a subject nor verb.
Option B is incorrect because this is also a phrase.
Option D is incorrect because the answer lies in C.