Which of the following contracts does not need to be in writing to be valid?

Leases for one year do not need to be in writing to be valid because California law allows for verbal leases that are less than one year in duration. This means that if the lease agreement is made orally and is intended to last for a year or less, it is generally recognized as valid, although it is highly advisable to have a written agreement for clarity and enforceability purposes.

In contrast, real estate sales contracts, mortgage agreements, and partnership agreements have specific legal requirements that mandate they be in writing. The Statute of Frauds, a legal doctrine that requires certain contracts to be in writing to be enforceable, applies to real estate transactions, which include sales contracts and mortgage agreements. Similarly, partnership agreements, especially those that involve significant commitments or terms, are also typically required to be in writing to ensure that all parties understand their rights and obligations clearly. This is crucial to prevent misunderstandings and disputes in the future.