Final answer:
The sale is legally binding upon signing the written contract and establishing escrow.
Step-by-step explanation:
The correct statement is d. The sale is legally binding upon signing the written contract and establishing escrow. When Maldonado Gastelum and Candice Dubois signed the written contract and established escrow, they entered into a legally binding agreement. Escrow is a process in which a neutral third party holds the funds and documents until specific conditions are met and the transaction is finalized. The physical transfer of the house and the inspection by Maldonado Gastelum are important steps in the process, but they do not determine the legality of the sale.