In which of the following options the order of arrangement does not agree with the variation of property indicated against it?
(a) I < Br < Cl < F (increasing electron gain enthalpy)
(b) Li < Na < K < Rb (increasing metallic radius)
(c) Al3+ < Mg2+ < Na2+ < F- (increasing ionic size)
(d) B < C < O < N (increasing first ionization enthalpy)