You place a book on top of a spring and push down, compressing the spring
by 10 cm. When you let go of the book, it is pushed up by the spring. Which
statement describes what happens to the energy of the spring-book system?

A The kinetic energy of the system decreases

B. The total energy of the system increases

c The gravitational potential energy of the system increases

D
The elastic potential energy of the system increases.