The first gateway bank just introduce the "money now" checking system. The bank requires a minimum balance of $3000 in order for the customer to be able to write as many checks as desired without paying any service charge. As a poromotional scheme, Geateway will give away popular brass belt buckles to new checking account customers. These buckles had been given to savings account depositors, and have proven very popular. The additional brass buckles now required have created an inventory problem. Mary kaye snyder, assistant manager of customer services, has estimated the following information: D= 800 buckles per year HC = $3 per buckle per year OC = $20 per order How many buckles should Mary Kaye order at one time? Determine the total annual inventory cost for the optimal order quantity.