Wisconsin real estate contracts must be:

A is incorrect because verbal contracts for real estate violate the Statute of Frauds. While verbal agreements might be binding in other contexts, real estate transactions require written documentation to be legally enforceable in Wisconsin.

C is incorrect because while notarization adds authenticity to a document, it is not a requirement for basic contract enforceability under Wisconsin real estate law. Notarization serves to verify identities but isn't mandated for validity.

D is incorrect because witnessing by two people is not a statutory requirement for enforceable real estate contracts in Wisconsin. While witnesses can provide additional evidence, they are not necessary for basic enforceability.