Which sentence correctly uses nonessential appositive commas?

Which sentence correctly uses nonessential appositive commas?

• A. The author, a renowned writer, attended the conference.
• B. The author a renowned writer attended the conference.
• C. The author, a renowned writer attended the conference.
• D. The author a renowned writer, attended the conference.

Answer: (A)

Nonessential appositive phrases add extra detail about a noun but aren’t needed to identify it, so they’re set off with commas. In this sentence, “a renowned writer” renames “the author” without being necessary to know who the author is, and you could remove it and still have a complete sentence: The author attended the conference. That’s why the correct punctuation places a comma before and after the appositive: The author, a renowned writer, attended the conference. The other forms mess up the punctuation by missing one of the commas or by making the appositive seem essential, which changes the meaning or creates a grammatical error.