Answer:
An implied contract
Step-by-step explanation:
An implied contract refers to an agreement between two or more parties where each party consents to take specific action even though there are no signed documents. The consent is derived by the acts, circumstances, or conduct of the parties. An implied contract is legally enforceable.
The act of boarding a bus is an example of an implied contract. Once on the bus, there is an implied contract that the bus will take you to your destination. The fare you pay is the consideration. The same principle applies to Luo and Mark. They have an implied contract that Mark will repair Luo's shoe. After the repairs, Luo should pay for the work done.