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