b. Factory A burns fossil fuel which produces toxins that reduces crop yield for Farmer B. The prot functions for the factory and the farmer are: W4 = 900 + 90x 9x2 1:3 = 900 603: Where it is the number of fuel in tonnes per year that factory A burns. i. If the externality is ignored, show that the amount of fuel that the factory will burn will be above the social optimum. [6 marks] ii. Find the optimal Pigovian tax that should be levied on the factory to correct the externality. [4 marks]