5. XYZ Company is a wholesaler of children's toys. Backorder is possible for the toy car. The annual demand of the toy car is 30.000 pieces, the holding cost is 2 TL / unit and the ordering cost is 15 TL. Backorder cost is 10 TL per unit. There are 200 working days in a year and lead time is 3 days. According to these information, a) What is the optimal highest positive stock level for the toy car? (5p) b) What is the optimal highest negative stock level? (5p) c) Calculate the periods of time when the demand is met and not met. (5p)