Kyle's utility function is U(x, y) = xy. Kenny's utility function is U(x, y) = 1, 000xy + 2, 000. Shelley's utility function is U(x, y) = xy(1 - xy). Es- ther's utility function is U(x, y) = -1/(10 + 2xy). Sharon's utility function is U(x, y) = x(y + 1,000). Stan's utility function is U(x, y) = 0.5xy -10, 000. Jimmy's utility function is U(x, y) = x/y. Herbert's utility function is U(x, y) = -xy. a. Who has the same preferences as Kyle? b. Who has the same indifference curves as Kyle? c. Explain why the answers to (a) and (b) differ