A Agrees to Paint B's House

Multiple Choice

A agrees to paint B's house.B then says to A,"If you paint my house,I'll give you $500.00." In this situation

A) the first agreement does not include the price,but the second agreement does.
B) together,the promise to pay and the first agreement to paint form one whole contract.
C) the entering into the main contract is the consideration for the collateral contract.
D) the promise to pay $500.00 is collateral to the first agreement to paint.
E) all of the above