Answer: The sentence which contains a dependent clause that is used as an object is C. The child finally admitted that he had eaten the cookie.
Explanation: A dependent clause is a clause that cannot stand alone as a sentence because it does not express a full idea. There are three main types of dependent clauses: adjective clauses, adverbial clauses and noun clauses. In the sentence provided, "that he had eaten the cookie" is a dependent clause since it does not express a complete thought. Moreover, "that he had eaten the cookie" is a noun clause and it is functioning as the direct object of the verb "admitted", that is to say that "that he had eaten the cookie" is the recipient of the action denoted by the verb.
