Logistics Management course; please a step by step answer. thanks.

per Harley purchases components from 4 suppliers. Components purchased from Supplier A are priced at $5 each and used at the rate of 20,000 units per month. Components purchased from Supplier B are priced at $4 each and are used at the rate of 2,500 units per month. Components purchased from Supplier C are priced at $5 each and used at the rate of 900 units per month. Components purchased from Supplier D are priced at $6 each and used at the rate of 100 units month. Currently, Harley purchases a separate truckload from each supplier. As part of its JIT drive, Harley has decided to aggregate purchases from the four suppliers. The trucking company charges a fixed cost of $400 for the truck with an additional charge of $100 for each stop. Thus, if Harley asks for a pickup from only one supplier, the trucking company charges $500, from two suppliers, it charges $600, from three suppliers, it charges $700; from three suppliers, it charges $800. Suggest a replenishment strategy for Harley that minimizes annual cost. Assume a holding cost of 15 percent per year. Use the three approaches to figure out the replenishment strategy for Harley that minimizes annual cost