The correct answer will be C. Carbon and Oxygen because these both are non metals and non metals react colvalently (i.e share electrons) while when metals react with a non metals they react ionically (i.e lose and gain electrons)
Answer is: C is equal to 2, D is equal to 6 and E is equal to 1.
C, D and E represent number of electrons on each atomic orbital in sodium atom.
Electron configuration of sodium atom: ₁₁Na 1s² 2s² 2p⁶ 3s¹.
Atomic number of sodium is 11, it means that it has 11 protons and 11 electrons, so atom of sodium is neutral.
C, because that is usually what waves are meant for. :)