Suppose the price of a soda is $2 each, the price of a hot dog is $3 each and the budget is $20. If the marginal utility of the fourth soda is 100 and the marginal utility of the fourth hot dog is 150, to maximize utility, a person will buy
A: 4 sodas and 4 hot dogs.
B: more hotdogs than 4 and fewer sodas than 4 because hot dogs provide more utility.
C: buy more sodas than 4 to increase their utility.
D: fewer sodas than 4 and more hot dogs than 4.