Hw question please help

12. (8 points) Consider the following graph depicting the competitive market for steel. 20 Price of Steel ($) - Demand - Supply . . . . . . Social Cost 0 4 6 8 10 12 14 16 18 20 Quantity Steel (tons) A. In a free market with no restrictions, what is the equilibrium quantity and price of steel? B. The above graph depicts an externality from steel production of $4 per ton of steel. Suppose the government sets a tax on steel of $4 per ton of steel. What quantity of steel would be produced? What price would buyers pay? C. Suppose the externality in this graph results from carbon emissions, and that producing one ton of steel generates two tons of carbon emissions. When the externality is $4 per ton of steel as in part (b), what is the quantity of carbon demanded? What is the carbon price (i.e. price per ton of carbon)? D. Continue to assume that producing one ton of steel generates two tons of carbon emissions. Suppose new research indicates that the value of the externality is $8 per ton of steel rather than $4 per ton of steel. Given this new value of the externality, what is the quantity of carbon demanded? What is the carbon price (i.e. price per ton of carbon)