Which one of the following statements is best? A. The level of safety stock maintained is greater if mean absolute deviation (MAD) is used rather than standard deviation in estimating forecast errors. B. When no safety stock is maintained, stockouts will occur during approximately 60% of the cycles. C. The level of safety stock maintained decreases when the standard deviation of demand during leadminustime increases. D. The level of safety stock maintained decreases when the desired cycleminusservice level decreases.