Hannah has agreed to buy Greg's car, but the two have not agreed on the price. When there is no agreement in a sales contract as to price, what effect does it have on the contract?

a$.$ There is no contract, because the agreement is not definite and certain enough.

b$.$ There is a contract, with the price being a reasonable price at the time the agreement was made.

c$.$ There is a contract, with the price being whatever Greg decides.

d$.$ There is a contract, with the price being a reasonable price at the time of delivery.