Cindy is buying a car from robert for $4,500. robert has agreed to accept a down payment of $500 and 16 consecutive monthly payments of $250 from cindy to pay the car off. in agreement, cindy writes up the following contract: “i agree to pay robert a down payment of $500 in addition to 16 payments of $225 in exchange for this car.” robert reads the contract and hands it back to cindy without signing it. which of the following is not a change robert should ask cindy to make to the contract?