Which sentence correctly uses a non-defining (nonrestrictive) clause?

Which sentence correctly uses a non-defining (nonrestrictive) clause?

• A. There are lots of movies made about a post-apocalyptic world.
• B. There are lots of movies made about a post-apocalyptic world which is popular among teens.
• C. There are lots of movies made about a post-apocalyptic world, which is popular among teens.
• D. There are lots of movies made about post-apocalyptic world.

Answer: (C)

Non-defining (nonrestrictive) clauses add extra information about a noun and are always set off by a comma. They describe the whole preceding noun phrase, and if you remove the clause, the sentence still makes sense. In this sentence, the noun phrase is “a post-apocalyptic world.” The clause “which is popular among teens” provides additional information about that world; it doesn’t identify which world is being discussed, it just adds that this world is popular with teens. Because this information is non-essential, it should be separated by a comma: a post-apocalyptic world, which is popular among teens. The other options don’t meet this punctuation rule. One lacks the required comma, making the clause feel essential instead of extra; another misses the article or has other phrasing that doesn’t read as a natural non-defining clause.

Non-defining (nonrestrictive) clauses add extra information about a noun and are always set off by a comma. They describe the whole preceding noun phrase, and if you remove the clause, the sentence still makes sense.

In this sentence, the noun phrase is “a post-apocalyptic world.” The clause “which is popular among teens” provides additional information about that world; it doesn’t identify which world is being discussed, it just adds that this world is popular with teens. Because this information is non-essential, it should be separated by a comma: a post-apocalyptic world, which is popular among teens.

The other options don’t meet this punctuation rule. One lacks the required comma, making the clause feel essential instead of extra; another misses the article or has other phrasing that doesn’t read as a natural non-defining clause.