4. Dean\&Sons Inc. needs to decide on the location of two new warehouses. The candidate sites are A, B, C , and D. Each of these sites will have a monthly capacity of 500 units. The warehouses will need to ship to three marketing areas: E,F, and G. The corresponding monthly requirements are 400,300 , and 300 units, respectively. The following table provides the monthly fixed costs for operating warehouses at each potential site, and the cost to ship one unit between each location and destination: In addition, the following conditions must be met by the final decision: (i) A warehouse must be opened in either A or D, or possibly both; and (ii) if a warehouse is opened in B, then one must also be opened in C. Which two sites should be selected for the new warehouses to minimize the total fixed and shipping costs? (a) Formulate this problem. (b) Solve it using Excel. (c) State the recommendation