A cart starts at Point A with 300 J of energy. It rolls down the track and hits the spring at the end of the track. The system includes only the Earth, the cart, and the track, and it acts as an isolated system. Which choice best describes the energy in the system when the cart is stopped by the spring at Point D?

At Point D, the system has more than 300 J of elastic potential energy and gravitational potential energy combined. It has elastic potential energy because the spring is compressed, and gravitational potential energy because the cart is at some position above the ground. Some energy was gained during transformation.
At Point D, the system has more than 300 J of elastic potential energy and gravitational potential energy combined. It has elastic potential energy because the spring is compressed, and gravitational potential energy because the cart is at some position above the ground. Some energy was gained during transformation.

At Point D, some of the original 300 J of gravitational potential energy has been converted to elastic energy and some has been converted to thermal energy. It has elastic potential energy because the spring is compressed, thermal energy due to energy transformation and friction, and gravitational potential energy because the cart is at some position above the ground. All the energy was conserved.
At Point D, some of the original 300 J of gravitational potential energy has been converted to elastic energy and some has been converted to thermal energy. It has elastic potential energy because the spring is compressed, thermal energy due to energy transformation and friction, and gravitational potential energy because the cart is at some position above the ground. All the energy was conserved.

At Point D, the system has less than 300 J of elastic potential energy because the spring is compressed. There is no kinetic energy because it is not moving nor any gravitational potential energy because it is not above the track. Some energy was lost during transformation.
At Point D, the system has less than 300 J of elastic potential energy because the spring is compressed. There is no kinetic energy because it is not moving nor any gravitational potential energy because it is not above the track. Some energy was lost during transformation.

At Point D, the system has exactly 300 J of elastic potential energy and thermal energy. There is elastic potential energy in the system because the spring is compressed. There is thermal energy in the system due to energy transformation and friction. There is no kinetic energy because it is not moving nor any gravitational potential energy because it is not above the track. All the energy was conserved.
At Point D, the system has exactly 300 J of elastic potential energy and thermal energy. There is elastic potential energy in the system because the spring is compressed. There is thermal energy in the system due to energy transformation and friction. There is no kinetic energy because it is not moving nor any gravitational potential energy because it is not above the track. All the energy was conserved.