The plant manager's overall conclusion is that they can greatly reduce the amount of sulfur dioxide their copper-smelting plant releases into the atmosphere by using a new process. So, the supervisor is agreeing with this. However, the supervisor states that the latest closed furnaces are extremely fuel-efficient.
What do we know about fuel-efficiency from the plant manager? She states that the new equipment is not only expensive to buy and install, but it also costs more to run than the current process. So the plant manager thinks that the new system is not as fuel efficient and therefore costs more to run than the current system, i.e. answer choice (B): whether the new copper-smelting process is more expensive to run than the current process.
Hope that helps! Please let us know if you have any other questions.
