Missouri real estate contracts must be:

While verbal contracts are generally valid for many transactions, Missouri's Statute of Frauds specifically requires real estate contracts to be in writing. This legal requirement exists because real estate transactions involve significant value and complexity, making written documentation essential to prevent disputes over terms and conditions. Verbal agreements for property sales, leases, or transfers are not enforceable in Missouri courts.

C is incorrect because while notarization adds authenticity to a document, it's not a requirement for real estate contracts to be enforceable under Missouri law. Notarization is an extra step that may be required for certain documents like deeds but not for contracts themselves.

D is incorrect because witnessing alone doesn't satisfy the Statute of Frauds requirement for real estate contracts. While witnesses may be present when a contract is signed, they don't substitute for the written requirement itself.