The annual demand, ordering cost, and the annual inventory carrying cost rate for a certain item are D = 600 units, S = $20/order and I = 30% of item price. Price is established by the following quantity discount schedule. What should the order quantity be in order to minimize the total annual cost? Quantity 1 to 49 50 to 249 250 and up Price $5.00 per unit $4.50 per unit $4.10 per unit.