Suppose that the daily demand for an item has mean 80 and standard deviation 30. The supply lead time has mean 3 days and standard deviation 1 day. You are using the base-stock policy to order the item every day. Which one of the following would have the biggest impact on safety stock reduction? Group of answer choices Reducing average lead time by 1 day Reducing lead time standard deviation by 0.2 day Reducing daily demand standard deviation by 10 units Reducing average lead time by 0.5 day and reducing daily demand standard deviation by 5 units