Answer: Quasi-contract
Step-by-step explanation:
The quasi-contract is one of the type of retroactive agreement between the two parties and this contract is basically created for the purpose of manage the various types of circumstances such as unjust enrichment regarding the various types of products and the services.
The quasi contract is basically created by a judge in the court too avoid all the conflicts in the party so that both the parties manage their expenses accurately.
According to the given question, Mason can seek the recovery on the basis of the quasi-contract between the Chenao and Mason exchange agreement. Therefore, Quasi-contract is the correct answer.