(a) a contract which provides for the purchase and sale or exchange of residential real property;
(b) a lease with an option to purchase residential real property;
(c) a lease-with-obligation-to-purchase agreement for residential real property; or
(d) an installment land sale contract for residential real property. 5. "Residential real property" means real property improved by a one to four family dwelling used or occupied, or intended to be used or occupied, wholly or partly, as the home or residence of one or more persons, but shall not refer to (a) unimproved real property upon which such dwellings are to be constructed, or (b) condominium units or cooperative apartments, or (c) property in a homeowners' association that is not owned in fee simple by the seller. 6. "Transfer of title" means delivery of a properly executed instrument conveying title to residential real property and shall include delivery of a real estate purchase contract that is a lease or installment land sale contract.