$(4)$

Amy agrees to purchase a car from Matt, provided that Matt repairs the engine before the delivery date specified in the contract. The contract explicitly states, "The sale is contingent upon the successful repair of the engine by Matt before the agreed$-$upon delivery date Amy will have no obligation to purchase the car if these repairs are not successfully made."

Upon inspection of the car on the delivery date, Amy discovers that the engine is still faulty, and Matt failed to fulfill the repair condition as stated in the contract.

What type of contractual condition is the repair of the engine?

A simultaneous concurrent condition.

An express condition precedent.

An implied partial condition.

An implied conditional condition.

An express condition subsequent.