Answer: D
Explanation: Look at the figure, we can conclude that the correct answer is
X: Low potential energy
Y: High potential energy
Z: Flow of electrons
Because electrons flow where there is difference in potential energy. And electrons move from a region of high potential energy to a region of low potential energy.
Since the arrow is pointing to X, that means
Z is the flow of electrons, X is of low potential energy and Y is of high potential energy.
