please show all work steps and solution with explanation and rules

2. Harley purchases components from three 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. Currently, Harley purchases a separate truckload from each supplier. 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; and from three suppliers, it charges $700.) Harley incurs a holding cost of 20 percent per year. a) What is the total annual cost (sum of ordering and holding costs) if Harley decides to order each model independently (i.e each model is ordered and delivered independently). ( 20 points) b) What is the total annual cost (sum of ordering and holding costs) if Harley decides to order each model jointly (i.e each model is included in every order). ( 20 points)