C. If you really stop and think about it, C is the most definite answer.
The word "them" in the sentence is used as the indirect object. The correct answer would be option B. It is used as the indirect object because it is being affected by the verb used in the sentence. The subject or the doer of the action is "sandy", the verb is "showed" and the direct object is "her coin collection" making "them" as the indirect object.
The sentence that is correctly construed with an independent clause and a dependent clause is A) As they examined the evidence afresh, they thought of a completely different explanation.
The other sentences don't have dependent clauses, only phrases.
