Party A and Party B have reached an agreement that Party A will provide Party B with a house for free and Party B will teach Party A's daughter to play the piano for free. What kind of contract does this belong to? Should I choose ACD?

Since CD is no longer explained, let's use common sense to understand it.

Nameless contract refers to the contract that is not stipulated in the specific provisions of contract law, so nameless contract is chosen.

As for B, personally, this kind of contract is similar to a lease contract, that is, one party rents a house and the other party uses labor as the rent, so it does not conform to the specific types of actual contracts in the traditional sense, such as custody, deposit and natural person loan. From the nature of the contract, similar to leasing, leasing is a commitment contract, that is, it takes effect immediately after the contract is signed, and there is no need to deliver the house. The same is true in this case. There is no need to teach children piano, and the contract will take effect after moving into the house.