Choice "D" is correct. Where a debtor has paid more than 60% of the price of consumer goods collateral and the creditor repossesses the collateral after default, the creditor must sell the collateral within 90 days unless the debtor agrees otherwise.
Choice "a" is incorrect. A debtor has a right to redeem before collateral is sold, but not after it is sold.
Choice "b" is incorrect. After collateral is sold, the proceeds go first to the costs of the sale, next to satisfy the secured party, then to any other party with an interest in the collateral. Only if there is a surplus can the debtor recover any of the sale price.
Choice "c" is incorrect. The debtor may allow the creditor to keep the collateral in satisfaction of the debt, but has no power to prevent a sale if the creditor does not want to retain the collateral in satisfaction.