5. (14 marks) Plastic Fab Inc is a local company that has just started manufacturing medical face shields for use in health care facilities. They purchase the head strap and connections from a supplier in the U.S. who lists these prices: less than 1,000, $5.00 each; 1,000 to 3,999, $4.95 each; 4,000 or more, $4.90 each. Ordering cost is $50 per order, annual holding cost is 20 percent of purchase price and annual usage is expected to be 4,900 shields. a) (9 marks) Determine the order quantity that will minimize total cost. b) (3 marks) Plastic Fab Inc has just identified a local supplier of the head strap and connections for a fixed price of $4.85 each (holding and ordering costs the same as in part a). What is the EOQ at this price? Based on the total annual costs, should Plastic Fab Inc go with this local supplier I c) (2 marks) Provide two reasons why inventory is held