If you have left your last job to join an MBA program, the interviewer will likely dodge this question onto you. When you answer, be humble and grateful for your previous job experience. Do not say, "There was nothing fruitful" or "I was underpaid." Instead, put it positively. "I have learned numerous qualities and skills from my previous job. However, I identified that the job might limit my abilities and future growth. Thus, I decided to add the icing and broaden my skill set by joining an MBA program".