A shoe company forecasts the following demands during the next six months: month 1-200; month 2-260; month 3-240; month 4-340; month 5-190; month 6-150. It costs $7 to produce a pair of shoes with regular-time labour (RT) and $11 with overtime labour (OT). During each month, regular production is limited to 200 pairs of shoes, and overtime production is limited to 100 pairs. It costs $1 per month to hold a pair of shoes in inventory. (a) Formulate a balanced transportation problem, using the Tableau format, to minimize the total cost of meeting the next six months of demand on time. (b) Using the Northwest Corner method, find a basic feasible solution to the problem. (c) Solve your problem using EXCEL.