Answer:
D is the answer
Explanation:
According to the ideal gas equation:
\(\frac{PV}{T}=nR\)
The nR are constant because you are not letting molecules of the gas scapes or enter the container even if you double the size, so in order to keep the right side constant as the Volume increases, the pressure must decrease (this is thinking that temperature is the same through all the process), and with more space to move, the collision between particles decreases too.
The thermal energy is linked to the collision between particles, if the number of collisions decreases, then the thermal energy decreases because the total kinetic energy is less now, so in general the energy in the system is less.
Where did all that energy go? it has been lost at the moment of the expansion of the volume, a work has been done to the surroundings
