Choose the answer which best rewords the italicized portion. If you think the original wording is best, choose option A.
Etiquette, which is sometimes unwritten, is a code that governs the expectations of social behavior of people.
A)Etiquette, which is sometimes unwritten, is
B)Etiquette, that is sometimes unwritten is
C)Etiquette, that is sometimes unwritten, is
D)Etiquette which is sometimes unwritten is

Question

Quizplus · Accepted Answer

The best choice is "Etiquette, which is sometimes unwritten, is"
The clause "which is sometimes unwritten" includes relevant information, but is not needed to complete the sentence. Therefore, it is a non-restrictive clause and should be offset by commas at the beginning and at the end of the phrase. "Which" is a pronoun used with non-restrictive clauses. Generally, "that" is a part of a restrictive clause.

Choose the Answer Which Best Rewords the Italicized Portion