Suppose demand is QD = 9 - P and supply is Qs = P. Price ($) There is a constant positive externality of $4 per 14 unit (marginal external benefit, MEB = $4). Find the 13- market equilibrium quantity and the socially optimal 12- quantity. The market equilibrium quantity is 4.5 . (Round your answer to one decimal place.) The socially optimal quantity is 6.5. (Round your answer to one decimal place.) Show the supply, demand, and marginal social benefit curves on the graph provided. 1.) Using the line drawing tool, sketch the demand curve based on the demand equation provided. Label your line 'D'. 1 2 3 4 5 6 7 8 9 10 11 12 13 1 2.) Using the line drawing tool, sketch the supply curve Quantity based on the supply equation provided. Label your line 'S'. 3.) Using the line drawing tool, sketch-the marginal social benefit curve based on the information provided. Label your line 'MSB'. Carefully follow the instructions above and only draw the required objects