In case of transfer by real property sales contract, as defined in Section 2985 of the Civil Code, as soon as practical before execution of the contract. For the purpose of this subsection "execution" means the making or acceptance of an offer. With respect to any transfer subject to Subsection A or B, the transferor shall indicate compliance with this chapter either on the receipt for deposit, the real property sales contract, or any addendum attached thereto or on a separate document.