Delta Company produces a single product. The cost of producing and selling a single unit of this product at the company's normal activity level of 60,000 units per year is: The normal selling price is $21 per unit. The company's capacity is 75,000 units per year. An order has been received from a mail-order house for 15,000 units at a special price of $14.00 per unit. This order would not affect regular sales. Ignore the one-time special order noted above. Instead, assume the company has 1,000 units of this product leftover and unsold from last year that are inferior to the current model. The units must be sold through regular channels at reduced prices. What unit cost is relevant for establishing a minimum selling price for these leftover units? Explain. What would be the minimum selling price per unit in this situation