Jos Martinez of El Paso has developed a polished stainless-steel tortilla machine that makes it a "showpiece" for display in Mexican restaurants. He needs to develop a 5-month aggregate plan. His forecast of capacity and demand follows: Demand Capacity Month 1 150 Month 1 160 Month 1 130 Month 1 200 Month 1 210 Regular Overtime 150 20 150 20 150 150 150 10 10 10 Additional information: Subcontracting: 100 units available over the 5-month period, Beginning inventory: O units Costs: Regular time cost per unit = $100 Overtime cost per unit = $125 Subcontract cost per unit = $135 Inventory holding cost per unit = $3 Assume that back-orders are not permitted. a. Using the transportation method, what is the total cost of the optimal plan? [Select] b. Does any regular time production go unused? [Select] If so/not, how much is used or not used? [Select] c. What is the total cost of the plan if ending inventory required for the next planning period is: 20 units (include holding costs in the overall calculation)? [Select]