Alpha Furniture company produces a specialty wood furniture product $,$ and has the following information available concerning its inventory items : relevant ordering costs per purchase order $ $120.$ Relevant carrying costs per unit $ $4.$ Annual demand is $16,200$ packages per year $.$ What is the reorder point assuming that the working days are $360$ per year and the lead time is $15$ days $?$ Select one : a $.450$ units b $.225$ units c $.150$ units d $.675$ units