If you did MBA in marketing and simply try to get a job because you have to, then it might not be the best answer to give to your interviewer. As honest as you might want to be, if you really want that job, you need to polish up your answer.
Interviewers are looking for people who are passionate about marketing- those who want to drive customer behavior and influence others purchasing decisions. You should also be self motivated and have the hunger to learn new marketing techniques.
If you hate marketing, do not go for it. If you think you can develop a passion for it, by all means choose to start a career in it.