A company is trying to establish a desirable transportation arrangement from its three plants to its four regional warehouses. The capacity of the three plants is 400, 600, and 1000 tons per day from plants A, B, and C, respectively. The daily demand of the four warehouses is 500, 400, 600, and 500 tons for warehouses W, X, Y, and Z, respectively. Set up an initial solution matrix for the transportation problem.