Electrons in an atom revolve around the nucleus in certain selected concentric paths which are called orbits. Which of the following orbit do you think will have highest energy?
N orbital
The energy of the outermost orbital is highest. The energy of the electron increases when the electron moves from K to L, M, N orbits respectively.
In the given options N is the outermost orbit and has the highest energy. Electrons in outer shells have higher average energy and travel farther from the nucleus than those in inner shells.