answer and shownsteps please

Question 2- Mohsen as the operations manager of a manufacturing firm wants to make purchasing decisions for a specific item. The cost of carrying an item is $16 per year. The ordering cost is $75 per order. One year is 300 working days. His current inventory management policy is summarized in the chart below: (present the details of calculations) a- Calculate the demand per year for this item. b- Based on the Mohsen's current practice, calculate the annual Inventory holding cost, annual ordering cost and annual total cost (If you could not calculate demand in part a, use D=9920 per year). c- Is Mohsen's current practice an optimal inventory policy? (show the answer mathematically by comparing total costs)