Ken Consumes Two Goods,Sprite and Potato Chips

Multiple Choice

Ken consumes two goods,Sprite and potato chips.Sprite costs $1 per can,and he consumes it to the point where the marginal utility he receives from his last Sprite is 3.Potato chips cost $2 per bag,and the relationship between the marginal utility he gets from eating a bag of potato chips and the number of bags he eats per month is as follows:

If Ken is maximizing his utility,how much does he spend on potato chips each month?

A) $2
B) $6
C) $8
D) $12