Which of the following utility functions V is a positive monotonic transformations of the corresponding utility functions U? O A. U = x1-2x2-2 and V = x12x22 O B. U=x12x22 and V = x1-3x2-3 + 100 O C. U = x12x22 and V = x14x24 +100 O D. U = x12x22 and V = x1-6x2-6