The bolded verb in this sentence is written in the conditional mood. Option C is correct.
A conditional mood is the form of a verb which is employed in order to make requests or expression of under what condition something would happen. It uses helping or auxiliary verbs including might, would, should and could. Sometimes it is connected to a clause which is in the subjunctive mood.
The conditional mood is made from the auxiliary verb would (also should with I and we) and the infinitive of the other verb without to