Both A and B are true. Check out this link: https://www.nerdwallet.com/blog/credit-cards/minimum-payment-credit-card/
I hope this helps!
The answer is 735 W.
He runs up the stairs, so he needs a total amount of energy = mgh = 5880 Joules.
For the rate: since he goes from zero energy to 5880 Joules over 8 seconds...
Joules/sec = 5,880/8 = 735 W