= (c) For a social welfare function W W(U(M),...,UH (MH)), where Mh is in- aw ath If Uh come, the "social marginal utility of income" is defined by M [M] Vh show that the social marginal utility of income is decreasing in Mh for a utilitarian social welfare function. Use this to argue that a fixed stock of income will be distributed equally. Show that the argument extends to any anonymous and concave social welfare function when all consumers have the same utility function. =