Which sentence correctly uses a nonrestrictive clause?

• A. The director, who oversees the project, approved the budget.
• B. The director who oversees the project approved the budget.
• C. The director oversees the project, approved the budget.
• D. The director approved the budget because oversees the project.

Answer: (A)

Nonrestrictive clauses add extra, nonessential information about a noun and are set off by commas. Here, the phrase "who oversees the project" describes the director but isn’t needed to identify which director is meant; the main idea is that the director approved the budget, and the added clause simply gives additional detail about the director.

This makes the sentence with the nonrestrictive clause the best choice because the information about overseeing the project is helpful but not essential to determine who approved the budget. The other options mismatch the nonrestrictive idea: without commas, a clause like "who oversees the project" would be restrictive, narrowing which director is being talked about. A sentence that combines two independent clauses with just a comma is a comma splice. And a clause introduced by "because" without proper subject structure doesn’t form a correct nonrestrictive construction.