There is no straight forward answer to this question - it should be based on what you have done till now, and what you want to do going ahead.
Take a step back and think about the common themes that emerge from your journey till now - that should tell you what areas you like to focus on. MBBs are more interested in your motivations behind your decision making for every professional step you take. And if you can tie your motivations behind every professional decision to a common theme which drives you, you should be in a good place.
Although what i gave you was not a straight forward answer to your question, I hope it helps. Happy to connect to discuss more. Feel free to DM!