I just need help with 'D'

Now Ray Smith wants you to take a look at the company's inventory position because he thinks that has decided to examine the situation for one key product-fly rods, which cost $320 each to purchase 10 percent of inventory value. The company has been buying 500 rods per order and placing another order when the stock on hand falls to 100 fly rods. Each time SSP orders, it incurs a cost equal to $64. Sales are uniform throughout the year. A. Smith believes that the EOQ model should be used to help determine the optimal inventory situation for this product. What is the EOQ formula? (6 pts) B. What is the formula for total inventory costs? (1 pt) C. What is the EOQ for the fly rods? What will the total inventory costs be for this product if the EOQ is produced? (2 pts) rods each time? (2 pts)