3. As an inventory manager you must decide on the order quantity for an item. Its annual demand is 2,000 units. Ordering costs (regardless of the order quantity) are $50 each time an order is placed, and the inventory holding cost is 25% of the unit price. (a) What is the optimal order quantity if the supplier is charging: a unit cost of $5 if your order quantity is less than 350 units, a unit cost of $4.9 if your order quantity is between 350 units and 999 units, a unit cost of $4.8 if your order quantity 1,000 units or more? (b) What is the optimal order quantity if the supplier is charging: a unit cost of $5, if your order quantity is less than 350 units, the first 349 units at $5, and the remaining units at $4.9, if your order quantity is between 350 units and 999 units, the first 349 units at $5, the second 650 units at $4.9, and the remaining units at $4.8, if your order quantity 1,000 units or more? (c) Which of the discount policies offered in parts (a) and (b), do you prefer to implement? (d) For each of the discount policies offered in parts (a) and (b), draw a figure that illustrates the total cost over time