O Sounds like the best answer
You can tell that the atom is in the excited state because:
- Electron configuration should follow the 2-8-8-2 rule, meaning that the inner shell should be filled before the next shell can start holding electrons.
- Instead of the atom's electron configuration being in the ground state at 2-8-8-1, electrons from the second shell have jumped to the third.
The answer c) A- Cell membrane because it selects what molecules enter/exit the cell
