Answer:
The answer to your question is D.
Explanation:
Potassium has 4 energy levels in the first level (A) has only 2 electrons,
in the second energy (B) level has 8 electrons, in the third energy level (C) also has 8 electrons and in the fourth energy level has only one electron.
Valence electrons are located in the outermost shell so Potassium has only one electron located in the shell D.
