Based on the agreement between Xi and Yard Work Inc. we can say that they had a unilateral contract when Yard Work Inc. began to work.
This is a contract where one of the parties who is the offeror, says that they will pay for the services of the other party after those services have been completed.
This is a unilateral contract because Xi is the offeror and promises to pay Yard Work after they had completed the tasks he wanted.
Find out more on unilateral contracts at https://brainly.com/question/4538548.