(Hint fexplanation: a pollution tax would put a price on pollution. What we mean by the \"demand for pollution\" is how much pollution these rms would \"buy\" from the government (by paying a tax) for any potential price. So, your answer should have price on the yaxis (or tax rate) and quantity on the xaxis, and it should trace out how much pollution the rms would \"buy\" for each price. To do this, realize that each rm will ei- ther buy none (instead abating all their emissions) or buy all the pollution they need (10 units per rm), except for those exact value cases. Try to think about what each rm will do and then build up the demand curve from there. Conceptually, remember that a demand curve is the marginal benet curve, and here the marginal benet of pollution to a rm is the fact that they don't have to pay the cost of abatement.)