The university is scheduling cleaning crews for its ten buildings. Each crew has a different cost and is qualified to clean only certain buildings. There are eight possible crews to choose from in this case. The goal is to minimize costs while making sure that each building is cleaned. The management science department formulated the following linear programming model to help with the selection process. Min 200x1 + 250x2 + 225x3+ 190x4 + 215x5 + 245x6 + 235x7 + 220x8 s.t. x + x + x5 + x7 2 1 (Building A constraint} x1 + x2 + x3 2 1 (Building B constraint} X6 + x8 > 1 [Building C constraint) x1 + x4 + x7 2 1 [Building D constraint} x2 + x7 2 1 {Building E constraint} x3 + x8 2 1 [Building F constraint] x2 + x5 + x7 2 1 {Building G constraint} x1 + x4 + x6 1 {Building H constraint} x1 + x6 + x8 2 1 [Building I constraint} x + x + x7 1 (Building J constraint] [1, if crew jis selected 10, otherwise = a. What is the cost of the optimal crew assignment? Cost of optimal crew assignment b. Which crews are assigned to work? Crew 1 will Crew 2 will Crew 3 will Crew 4 will Crew 5 will Crew 6 will Crew 7 will Crew 8 will (Use EXCEL or a LINEAR PROGRAMMING SOLVER.)