Answer:
B. You have to pay interest on credit cards but not on charge cards.
Explanation:
Credit cards and charge cards differ on the method of payment and on the interest credit cards charge you when you don't pay your full balance.
A credit card allows you to get credit and carry-over a balance at the end of the month, that's why you are charged an interest.
Charge cards don't extend you credit and are expected to be paid in full each month.