$(10$ pts$)$ DoorRed Pharmacy replenishes one of its best$-$selling drugs using a continuous review policy. Daily demand for the drug is normally distributed, with a mean of $300$ and a standard deviation of $100.$ The wholesaler can process a replenishment request in two days. The current replenishment policy is to order $1,500$ units when there are $750$ units on hand. a$)$ What is the cycle service level and fill rate that DoorRed achieves with its policy? $(2$ pt$)$ b$)$ If DoorRed wants to achieve a fill rate of $99\mathrm{.}9$ percent, how should it adjust the ROP? $(3$ pt$)$ DoorRed Pharmacy has decided to follow a periodic review policy to manage inventory