Answer: The correct answer is D,
Explanation :
Potential energy is the energy possessed by the body due to its position. It the work stored in the body. Its is maximum at initial position
Kinetic energy is the energy possessed by the body due to its motion. It is also defined as work required to accelerate the body of a given mass. It is maximum at final position.
At point A the cart is at its position with maximum potential energy. At the moment the carts starts moving down the potential energy starts decreases and kinetic energy increases potential energy is getting changed into kinetic energy. At point B the kinetic energy becomes maximum.
Hence, the correct answer is option D.