4. Aria contracted with Kasem to complete a small construction project by June 30 with $15,000 due on completion. Kasem wants to be paid early and on June 12 agreed with Aria to accept $12,000 on June 20 in full consideration of the construction contract. Which of following statements regarding the agreement to reduce consideration is true?

a) Aria and Kasem are both bound by the agreement to reduce the consideration.

b) Aria and Kasem are not bound to the reduction in consideration as this agreement was gratuitous.

c) Kasem is entitled to the remaining $3,000 and can sue Aria for this amount.

d) Kasem can change his mind prior to June 20 and require Aria to pay the full amount on June 30.