We have described the slope of an indifference curve as the marginal rate of substitution between the two goods. Imagining that c, is plotted on the vertical axis and c plotted on the horizontal axis, compute the marginal rate of substitution for the following utility functions. a. u(C,,C2) = In(c, ) + In(c2) b. u( c , (2 ) = VC+cz c. u(c ,c) = cic,, where a e (0,1) is some constant