A firm desires to control inventory levels so as to minimize the sum of holding and order costs. It costs the firm $50 to place an order. The firm estimates its annual carrying charge is 20%. Weekly demand is 100 units, and there are 50 weeks in the work year. The item costs $10 per unit. The lead-time for the product is 3 weeks. Assume that there are 5 working days per week. What quantity of items should the firm order each time so as to minimize total inventory costs, i.e., what is the EOQ?
A. 100
B. 224
C. 500
D. 1000
E. none of the above