Then safety stock justified by the carrying cost will be

Question

A company has an annual demand of 1000 units, ordering cost of Rs.100 per order and carrying cost of Rs.100 per unit-year. If the stock-outs are estimated to be nearly Rs.400 each time the company runs out-of-stock, then safety stock justified by the carrying cost will be                                                                     

      (a) 4                                                                    (b) 20

      (c) 40                                                                  (d) 100