If Water Became Very Scarce and Diamonds Became Very Plentiful

If water became very scarce and diamonds became very plentiful

A) the marginal utility of diamonds and water would both rise.
B) the marginal utility of both water and diamonds would both fall.
C) the marginal utility of diamonds would rise and the marginal utility of water would fall.
D) the marginal utility of water would rise and the marginal utility of diamonds would fall.