The correct option is B F<Cl>Br>I
Electron gain enthalpy becomes less negative on moving down a group due to increase in atomic size. However, the electron gain enthalpy of F is less negative than that of CI due to electron-electron repulsion in small-sized F atom. Thus, the correct order is F<Cl>Br>I.
F, Cl, Br and I have ΔegH values(in kJmol−1) -328, -349, -325 and -295 respectively.