Carrie promises Tim she will clean his house and in exchange, Tim promises to pay Carrie $50. This is an example of what type of contract?

A) A unilateral contract
B) A bilateral contract
C) An implied contract
D) A contract created through promissory estoppel
E) An invalid contract

Bilateral Contract

A type of contract involving mutual obligations whereby each party promises to perform an act in exchange for the other party's act.

Promissory Estoppel

A legal principle that prevents a party from withdrawing a promise made to a second party if the latter has reasonably relied on that promise to their detriment.