3. The water-diamond paradox can be explained by showing that

a. water's total utility may be lower than diamonds', but its marginal utility is higher

b. water's total utility may be lower than diamonds', and its marginal utility is lower as well

c. water's total utility is less than its marginal, but diamonds' total utility is higher than their marginal

d. water's total utility may be higher than diamonds', but its marginal utility is lower