Answer: The answer is most likely, "writing down your questions before you begin."
>This answer is probably correct since writing down your questions in the correct order and time will help the interviewer manage his time.
Explanation: This question can be subjective to the person, but logically the first one probably correct.
>The 2nd one does not really help the interviewer, as the interviewer is only showing his thesis to the interviewee, so he's helping the interviewee instead.
>In the 3rd one, the interviewer only explains the audience and purpose, neither will truly help the interviewer stay on track with his questions to the interviewee.