A force applied to a spring compresses the spring 15 cm, storing a certain amount of elastic potential energy. Then a larger force is applied to compress the spring a total of 30 cm. How does the elastic potential energy stored in the spring after it is compressed 30 cm compare to the elastic potential energy stored in the spring after it was compressed 15 cm?

a. The elastic energy stored in the spring when compressed 30 cm is the same as when it is compressed 15 cm.

b. The elastic energy stored in the spring when compressed 30 cm is twice as much as when the spring is compressed 15 cm. c. The elastic energy stored in the spring when compressed 30 cm is four times as much as when the spring is compressed 15 cm.