Payment of a secured claim shall be on the basis of the full amount if the creditor shall surrender the creditor’s security. If payment is not made on the basis described in paragraph (1) of this subsection, it shall be made as provided in subsection (b) or (c) of this section. If during administration, the creditor exhausts the security before receiving payment, the creditor is entitled to the full amount of the creditor’s allowed claim less the amount realized on exhausting the security. If the creditor has not then exhausted, or does not have the right to exhaust the creditor’s security, the creditor is entitled to the full amount of the creditor’s allowed claim less the value of the security determined by agreement, or as the court determines.