Answer:
The answer is letter C.
Step-by-step explanation:
Active voice refers to the forms of speech where the statements expressed indicate that the action is done by the subject. On the other hand, passive voice is the one where the subject doesn't perform the action, but receives it; it is characterized by the use of the auxiliary be+verb in past participle. Options A, B, and D have subjects that receive the action (return, write, read) and we can find the auxiliary be in different tenses and a verb in past participle. In option C the doer of the action is I which is also the subject.