While digging a basement for your new house, Davis Construction Company discovers dinosaur bones which weren't expected in the area. They ask for $10,000 more to complete the job and you reluctantly agree. Is this a valid contract?

	A.	No, because you did not give valid consideration.
	B.	No, because Davis did not give valid consideration.
	C.	No, because the contract was not in writing.
	D.	Yes.