In 1960, the average cost of a gallon of milk was $0.49. In 1985, the average cost of a gallon of milk was $2.26. Which of the following represents how to calculate the percent increase in the average cost of a gallon of milk from 1960 to 1985.
 A
 2.26−0.490.49
 B
 2.26+0.490.49
 C
 2.26−0.492.26
 D
 2.26+0.492.26
 which one