Why is the electron gain enthalpy of O or F less than that of S or Cl?

Options

A. O and F are more electronegative than S and Cl.
B. When an electron is added to O or F,it goe to a smaller(n=2) level and suffers more repulsion than the electron in S or Cl in larger level(n=3)
C. Adding an electron to 3p-orbital leads to more rpulsion than 2p-orbital.
D. Electron gain enthalpy depends upon the electron affinity of the atom.

Answer

B

Explanation

There is more repulsion for the incoming electron when the size of atom is smaller.