Gomer has just opened his auto repair business in a small industrial park located within the Weaver, the landlord, that his largest pieces of equipment $($tow trucks$)$ may not be parked restriction against parking equipment in the complex is:

a$.$ an unconstitutional regulation of private property.

b$.$ unenforceable unless signs are posted.

c$.$ enforceable as a private law.

d$.$ unenforceable unless a city zoning ordinance prohibits such parking.