It totally depends on your background and what are you trying ti achieve by an MBA, there cannot be a generic answer for this
I agree that the final answer depends on one's background. But surely people, especially those that have been successful in the application process, can provide some advice on how to best approach the question.
In general you'll want to be able to tell the story of "I'm currently at point X, I want to get to point Y in the short term and point Z in the longer term. The best and quickest way from X to Y is an MBA." Filling in those variables is going to be very different for each person. So, the best approach to this question is to really take the time to think through why you
want an MBA, and why now is the best time to get an MBA for you
. It's important that your answer be authentic to you and demonstrate that you understand what an MBA involves/provides and why it's the right move.