Poor people, who already purchase the cheapest food items - starches, frankfurters, beans and the like - have no items that they can economize when there is a rise in overall price of food.

A) that they can economize when there is a rise in overall price of food
B) on which there can be economizing when there is a rise in overall price of food
C) for economizing if there will be an overall rise in the price of food
D) on which to economize when overall prices of food rise
E) that can be economical when overall prices of food rise

I chose E, but OA is D..