A restrictive clause is one that

Alimits the meaning of the word it describes.
Bshould be set off by commas.
Cfunctions as an adverb.
Dusually occurs at the beginning of a sentence.

Verified Answer :

W0lf93

It is one that limits the meaning of the word it describes. It includes a sentence that does not use commas to describe that certain adjective. A restrictive clause is very much needed to try and describe the true meaning of what you are trying to explain in a sentence.

Answer:

A. limits the meaning of the word it describes.

Explanation: