Property owners who offer to sell any interest in a Historic Site, historic resource, or other real property located within a Historic District shall disclose to prospective purchaser(s) that the property is a Historic Site, historic resource, or is located within a Historic District in Prince George's County. The requirements of subsection (a) shall be met by delivering written notice to the prospective purchaser that is sufficient to inform the prospective purchaser that: Historic Sites, historic resources, and property located within a Historic District are subject to regulation as provided in the Prince George's County Code, Subtitle 29, Preservation of Historic Resources; and These laws, guidelines, and regulations may limit the extent to which the exterior features of the property being offered for sale may be modified or altered. The disclosure required by this Section shall be made prior to execution of a valid sales contract for the property.