Halflife, the option tells that at every Pareto optimal allocation total milk production is 8000. How can that be ?, Pareto optimal allocations can be anywhere along the line x=y. Moreover even if we get 8000 whether or not that is the actual optimal allocation depends on the initial endowment.. Correct me if I'm wrong.
Yeah we assume that social improvement has happened if total surplus increase because then the increased surplus can be redistributed between the agents and everyone can be at least made better off..
@halflife In 3rd degree price discrimination,we equate the marginal revenues but here we cannot do so because in the second market e>-1 i.e -0.10 which implies the MR<0.Also, when we equate the marginal revenues we assume MC in both markets to be equal.But since MR<0 in 2nd case we cannot equate it to positive MC and hence to the MR in first market.
So,by the intuition that elasticity is more in the first market it is feasible to lower the price to ensure more profits and raise the price in the inelastic mkt demand. so option (D)