To be honest, it’s up to you. If your actions are good then you’d move up. If they are an equal combination of good and bad, then you’d stay in the same caste. If they are like completely bad then you’re moving down.
Here’s an example answer:
“I believe that I am moving up based on my actions. Most of my actions are good since I volunteer at the local food shelter and make a change in my community. This is why I believe I am moving up in the caste since my actions are good.”