Kristi Spends All of Her Income on Tank Tops and Running

Multiple Choice

Kristi spends all of her income on tank tops and running shoes,and the price of a pair of running shoes is four times the price of a tank top.In order to maximize total utility,Kristi should buy

A) four times as many tank tops as pairs of running shoes.
B) four times as many pairs of running shoes as tank tops.
C) both items until the marginal utility of a pair of running shoes is four times the marginal utility of a tank top.
D) both items until the marginal utility of a tank top is four times the marginal utility of a pair of running shoes.