ABC Distribution has two plants (1, and 2) from which it ships product to four distribution centers (A, B, C, and D). The following table reports the shipping costs between each plant and distribution center, the plant manufacturing capabilities (in thousands), and the distribution center product demands (in thousands). WAREHOUSE A B Manufacturing C D Capability Plant 1 $7 $2 $5 $3 60 Plant 2 $8 $14 $8 $12 80 Demand 15 40 20 30 An optimal shipment plan is to be calculated by minimizing the total transportation cost, while ensuring that manufacturing capability at each of the plants is not violated, and demand at warehouses are met. Using optimization software, such as EXCEL'S SOLVER, find the optimal solution and then select the statement from among the following that is true. Select one: O a. The optimal transportation cost is $540. O b. The optimal transportation cost is $690. OC. The optimal transportation cost is $375