3. There are three industrial rms in a small town. Initial pollution level Cost of reducing pollution by 1 unit I_ - The government wants to reduce pollution to 120 units, so it gives each rm 40 tradable pollution permits. a) Who sells permits and how many do they sell? Who buys permits and how many do they buy? Briey explain Why the sellers and buyers are each Willing to do so. What is the total cost of pollution reduction in this situation? b) How much higher would the costs of pollution reduction be if the permits could not be traded