If one interrogates someone, they are asking them a question. All interrogative sentences or moods are questioning, which are usually indicated with a question mark at the end of the sentence.
Verbs in the interrogative mood are ones that show that one is questioning something or wants to know something. This is a trick question because it would appear that the answer is A because it is a question, but A is wrong because it asks for a verb in the interrogative mood, not the whole sentence.
If you look at C, you can see that there is the verb wonder. This is an interrogative verb because it shows that the subject is questioning something or wants to know something. Therefore, the correct answer is C.
