Which of the following sentences contains a dependent clause?
A. My mother, who never wastes anything, rinsed and saved the take -out boxes.
B. We were running late, and we had to skip stopping by the post office.
C. I had never been to New York before this spring
D. You should take an umbrella to the game.

The sentence that contains a dependent clause is (C) I had never been to New York before this spring.

A dependent clause is called dependent because it cannot stand alone in a sentence

Explanation:

A dependent clause can be defined as a  group of words that  contains a subject and a verb, but it is not a complete sentence and cannoyt stand alone as  a complete sentence .

A dependent Clause is dependent on an independent clause to become a sentence.

A dependent clause can be identified in  a sentence  by using dependent markers : after, as, although, because, before, even though, if, once, rather than, since, that, though, unless, until, when, whenever, whereas, while, among others.

In the above question the sentence (C)  I had never been to New York before this spring consist of a dependent marker (i.e before) so it is a dependent clause

we need to see the statements.