Why do induced dipole-induced dipole forces increase as the number of electrons in a molecule increases?

Question

a. More electrons make the electron cloud more polarizable.

b. More electrons means that there are more protons in the nuclei which hold the electrons more tightly and polarize them.

c. Molecules with more electrons are more likely to be held together by ionic bonds.

Answer 1

I wouldn't pick any of them; I would have preferred that one choice be because the electron cloud is larger which makes the atom more polarizable; however, a comes the closest.