Q4) The annual demand, ordering cost, and the annual inventory carrying cost rate for a certain item are D = 600 units, S = SR20 per 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? Price range Quantity Price Initial price 1 to 49 SR 5.00 per unit Discount price 1 50 to 249 SR 4.50 per unit Discount price 2 250 and more SR 4.10 per unit