Under which of the following coIf the lead-time for receiving the orders from the supplier doubles, the order quantity in the fixed order quantity model a. Halves. b. Doubles. c. Increasebyafactorof2. d. Noneoftheabove.nditions the critical fractile (service level) is negative? a) The salvage value is greater than the purchase price. b) The salvage value is less than the purchase price. c) The demand is normally distributed, and the z-value is negative. d) None of the above