Refer to the Figure Below

Refer to the figure below. An oxygen atom by itself is very reactive, whereas an oxygen atom that has combined with two hydrogen atoms to form a water molecule is very stable.What explains this observation?

A) Oxygen starts out with a total of eight electrons and becomes more stable when it adds more electrons.
B) The eight protons in the oxygen nucleus need additional electrons from hydrogen atoms to help neutralize their charge.
C) The two electrons in the innermost shell of an oxygen atom need two additional electrons to balance out.
D) The mass provided by the two hydrogen atoms adds to the mass of the oxygen atom, which increases the stability of the entire structure.
E) An oxygen atom only has six electrons in its valence shell and needs two electrons from hydrogen to fill this shell.