Which group of words is a sentence fragment?

A.

Mom says we should not open the refrigerator until power is restored.

B.

We lost power during the thunderstorm last night.

C.

Dad thinks the power will return in the afternoon.

D.

Until the thunderstorm took out the power last night

D.

Until the thunderstorm took out the power last night

Is it right or wrong?

The correct answer for the given question above would be option D. The group of words that is considered fragment is: Until the thunderstorm took out the power last night. A sentence can be considered a fragment if it lacks either the subject or the main predicate in the sentence, which makes its thought incomplete. In this fragment sentence, the subject is missing.