To be valid, restrictions in a grant deed need to:

Option A is incorrect because while restrictions should be in writing, simply being in a deed or agreement doesn't automatically make them binding on future owners. The restrictions must specifically intend to run with the land to be enforceable against subsequent purchasers.

Option B is incorrect because restrictions can be more restrictive than zoning requirements. In fact, many properties have private deed restrictions or covenants that impose greater limitations than what the zoning code requires.

Option D is incorrect because posting signs is not a legally sufficient method to establish binding restrictions that run with the land. While signs may inform current occupants, they don't create enforceable limitations on future owners.