Oh, Sunny. This revelation is really something.

This. This is it in a nutshell. Your ancestors may have made some terrible decisions. Maybe your ancestors were terrible people. That is not YOUR problem. All that is expected of you is to be a good person in your life. It's also why no one is entitled to reparations. You did not suffer. It's very sad and wrong if your ancestors did, but no one owes you money for that. 

Seeing her be humiliated is worth it.

How will people react when they learn some Africans sold other Africans into slavery?

She won't know how to act.

It's almost like human beings have been forcing other human beings they viewed as weaker or less than to do their labor for as long as recorded history.

Isn't that interesting?

Sunny better be ready to pay up. 

Again, that's (D) different. 

Oh, she will likely stop talking about that now.

Yes, go out and live your life, be successful, make friends, be normal and don't worry about the mistakes of your ancestors. If you happen to know your ancestors did bad things, be sure you stop the cycle. That's the best thing you can do and all you are responsible for pursuing.