Among halogens, the correct order of amount of energy released in electron gain enthalpy is

As we move from Cl to I, the electron gain enthalpy (i.e. energy released in electron gain) become less and less negative due to a corresponding increase in the atomic size. However, the electron gain enthalpy of F is less negative than that of Cl due to its small size. Thus, the negative electron gain enthalpy follows the order, F < Cl > Br > l