Answer: Option (B) is the correct answer.
Step-by-step explanation:
When the book was at the shelf, it had only potential energy as potential energy is the energy possessed due to the position of an object.
Therefore, when the book falls from the book shelf it gains kinetic energy as kinetic energy is the energy possessed due to the motion of an object.
Thus, when the books is falling from the top shelf then the motion of book increases therefore, we can conclude that the potential energy decreases as kinetic energy increases.