Which of the Following Is Not an Example of a Contract

Which of the following is not an example of a contract?

A) A written promise to give your husband a ring for Christmas
B) A verbal agreement to work for someone starting next week
C) A verbal agreement for the sale of a car where neither the money or the car has yet changed hands
D) An agreement not to sue someone for negligence in exchange for their promise to pay you a specified amount
E) An implied promise to pay for a meal when you order it