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 5.

A、Without changing her total expenditures, she could increase her utility by consuming more jam and less juice.
B、Without changing her total expenditures, she could increase her utility by consuming more juice and less jam.
C、Without changing her total expenditures on jam and juice, she could not increase her utility.
D、We can't tell whether any of the other statements are true or false without knowing the quantities she consumes.