1. Suppose that the utility function is U(a:, y) : 931/3 | yl/S, then X and y are: Hint: in this particular example, the gross complementarity or substitution among goods has the symmetry property. a ( (b ( Net complements and gross substitutes Net complements and gross complements (c d ) ) ) Net substitutes and gross substitutes ) Net substitutes and neither gross substitutes nor gross complements ) (e None of them