In a sentence containing a nonrestrictive clause, where should commas be placed?

• A. No commas around the clause.
• B. Commas around the clause.
• C. A colon before the clause.
• D. A dash after the clause.

Answer: (B)

Nonrestrictive clauses add information about a noun that isn’t essential to identifying it. Because this information is optional, it’s set off with commas on both sides. When you see a clause that could be removed without changing who or what the sentence is about, surround it with commas to show it’s additional detail. For example: The car, which I bought last year, needs new brakes. If you take out the clause, “The car needs new brakes,” the sentence still makes sense. That’s why commas around the clause are the correct choice. A colon before the clause isn’t used to introduce this kind of information, and a dash after the clause isn’t the standard marking for nonrestrictive material in careful writing.