Answer:
A. Electron clouds or energy levels
Step-by-step explanation:
Electrons can exist in two states:
- Stablized in electronic orbitals
- Freely moving
Electrons can exist in an electron cloud or energy level. Electron in an atoms have ability to change energy levels either by emitting or absorbing a photon that form the energy equal to the energy difference between the two levels.
Hence, the correct answer is A.