The correct option is D 3 > 2 > 1 > 4
+NH3 is most e− withdrawing since it is electron deficient and carrying a positive charge. Nitro group is also an electron withdrawing group. CN− is moree− withdrawing group than F− because fluorine being smaller in size, is already carrying a negative charge and cannot withdraw any more electrons.
Hence, the order is +NH3>NO2>CN−>F−