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 are set off by commas. The phrase "a renowned writer" describes the author but isn’t needed to identify which author attended; you can remove it and still have a clear sentence: "The author attended the conference." Because this extra information is nonessential, it should be enclosed by commas on both sides. That’s why the correct sentence places a comma before "a renowned writer" and another after it, giving: The author, a renowned writer, attended the conference. If the commas aren’t placed correctly or are missing, it either suggests the description is essential to identify the subject or creates punctuation errors, which is why the other forms don’t fit.