A company manufactures a product at its plants in A, B, C, and D, then ships the product to four customers in P, Q, R, and S, The monthly capacity of plants A, B, C, and D are 9800, 7500, 4500, and 7800 units, respectively. The monthly demand from customers P, Q, R, and S are 9600, 6800, 4200, and 8300 units, respectively. Use Excel Solver to find the optimal distribution plant that will give the lowest total monthly shipping cost if the shipping cost per unit (in dollars per unit) are as follows: from A to P, Q, R, and Sare 3,6,7, and 12 dollars per unit, respectively, from B to P, Q, R, and S are 15, 11, 4, and 9 dollars per unit, respectively; from C to P, Q, R, and S are 12,9,6, and 7 dollars per unit, respectively: from D to P, Q, R, and S are 20, 13, 9, and 4 dollars per unit, respectively. The optimal total shipping costs is dollars per month