Helen went to the grocery store to buy potatoes. The store charges $1.09 for each pound of potatoes. On the way out of the store, Helen picked up a gallon of ice cream at a cost of $4.73. If Helen spent $16.72 at the store, how many pounds of potatoes did she purchase? Assume tax is included in the given price. A. 10 B. 12 C. 5 D. 11