题目8单选题
Isobel consumes positive quantities of both jam and and juice. The price of jam is 5 cents per unit and the price of juice is 10 cents per unit. Her marginal utility of jam is 10 and her marginal utility of juice is 5A. Without changing her total expenditures, she could increase her utility by consuming more jam and less juiceB. Without changing her total expenditures, she could increase her utility by consuming more juice and less jamC. Without changing her total expenditures on jam and juice, she could not increase her utilityD. We can't tell whether any of the other statements are true or false without knowing the quantities she consumes