Which of the Following Situations Would Be Considered Ethical

Which of the following situations would be considered ethical?

A) The cashier at Wal-Mart gives you $5 more than you were supposed to receive and you don't do anything about it
B) You accidentally back into a car at Wal-Mart and leave your information for them to call
C) Receiving fake $20 bills and using them in a store while knowing they are fake
D) Finding a phone in a restaurant and keeping it