What is a contract?

What is a contract?
A . An agreement between two or more parties which creates no obligation to do a particular thing.
B . A contract is an agreement between two or more parties that does not establish an enforceable legal relationship.
C . Contract consists of reciprocal promise that the law will not enforce.
D . A contract is the result of a promise to do a certain thing in exchange for a promise from on their person.

Answer: D