A tutor is needed to help the student in understanding her lessons and in improving her study habits. The tutor does not, however, give the questions to an upcoming exam or do her assignments for her. Hence, the answer is D.
Understanding more about both the company you hope to work for and its competitors will help you appear competent and well prepared for the interview. It will also assist you in preparing good questions to ask of the interviewer if you are given the chance to do so.
I would choose around the Beginning of the AD time period so I could witness history pre-slavery, human life (especially in regards to health, such as diet) and aspects of religion.