In Which of the Following Contracts Is Consideration Not Required

In which of the following contracts is consideration not required?

A) Emerald promises to pay Gold $10 000 next week if he will transfer his car to her today.
B) Emerald enters into a deed which states that Gold will transfer ownership of his car to Emerald.
C) Emerald gives Gold $1.00 for his car,and Gold immediately transfers it to her.
D) Emerald promises Gold that she and her professional band will sing at his birthday in three months if he transfers his car to her next week.