Please explain why an installment land contract is a transfer of land or the transfer of interest of land. Which is it (transfer of land or transfer of interest of land) ---wouldn't it be a transfer of interest because she buyer is paying in installments toward the full purchase price?

Question A landowner mortgaged her land to a nationally chartered bank as security for a loan. The mortgage provided that the bank could, at its option, declare the entire loan due and payabile if all or any part of the land, or an interest therein, was sold or transferred without the bank's prior written consent. Subsequently, the landowner wanted to sell the land to a neighbor by an installment land contract, but the bank refused to consent. The neighbor's credit was good, and all mortgage payments to the bank were fully current. The landowner and the neighbor consulted an attorney about their proposed transaction, their desire to complete it, and the bank's refusal to consent. What would the attorney's best advice be? Even if the landowner transfers to the neighbor by land contract, the bank may accelerate the debt and foreclose if the full amount is not paid. B The due-on-sale clause is void as an illegal restraint on alienation of the fee simple, so they may proceed. C By making the transfer in land contract form, the landowner will prevent enforcement of the due-on-sale clause if the mortgage payments are kept current. D The only effect of the due-on-sale clause is that the proposed transfer will automatically make the neighbor personally liable on the debt, whether or not the neighbor specifically agrees to assume it