Plant Manager: We could greatly reduce the amount of sulfur dioxide our copper-smelting plant releases into the atmosphere by using a new process. The new process requires replacing our open furnaces with closed ones and moving the copper from one furnace to the next in solid, not molten, form. However, not only is the new equipment expensive to buy and install, but the new process also costs more to run than the current process, because the copper must be reheated after it has cooled. So overall, adopting the new process will cost much but bring the company no profit. Supervisor: I agree with your overall conclusion, but disagree about one point you make, since the latest closed furnaces are extremely fuel-efficient. The point about which the supervisor expresses disagreement with the plant manager is ['whether the new copper-smelting process releases less sulfur dioxide gas into the atmosphere than the current process', 'whether the new process should be adopted in the copper-smelting plant', 'whether the new copper-smelting process is more expensive to run than the current process', 'whether closed copper-smelting furnaces are more fuel-efficient than open furnaces']