Answer:
A. This is a bilateral, valid, executory contract
Step-by-step explanation:
As in the given scenario, the offer and acceptance is made between the Mary and Hal which reflect the valid contract as in this both parties have expresses to enter into a contract
Plus, it is a bilateral contract in which both parties agree to do his/ her positions.
And, it is also an executory contract in which the contract is completed at some future i.e in this case the contract is completed when delivery and payment are made.