In which of the following arrangements, the sequence is not strictly according to the property written against it?
(a) CO2 < SiO2 < SnO2 < PbO2
increasing oxidising power
(b) HF < HCl < HBr < HI
increasing acid strength
(c) NH3 > PH3 < AsH3 < SbH3
increasing basic strength
(d) B<C<O<N
increasing first ionisation enthalpy
