Which of the following sentences includes a correctly punctuated nonrestrictive phrase?

Question

1. My nephew being, only a toddler, did not understand the question.
2. My nephew being only a toddler did not understand the question.
3. My nephew, being only a toddler; did not understand the question.
4. My nephew, being only a toddler, did not understand the question.

Answer 1

The sentence that includes a correctly punctuated nonrestrictive phrase is:

4. My nephew, being only a toddler, did not understand the question.

In this sentence, the nonrestrictive phrase "being only a toddler" is correctly offset by commas.