In the following question, a sentence has been given in Active/Passive voice. Out of the four alternatives suggested, select the one which best expresses the same sentence in Passive/Active voice. The tutor always answers the students' questions.

• The students' questions is always answered by the tutor.
• Questions answered by the tutor are by the students.
• The students' questions are always answered by the tutor.
• Questions answered by the tutor is by the students.