Given below are two statements :
Statement (I) : The radii of isoelectronic species increases in the order.
${\rm{M}}{{\rm{g}}^{2 + }} < {\rm{N}}{{\rm{a}}^ + } < {{\rm{F}}^ - } < {{\rm{O}}^{2 - }}$
Statement (II) : The magnitude of electron gain enthalpy of halogen decreases in the order.
${\rm{Cl}} > {\rm{F}} > {\rm{Br}} > {\rm{I}}$
In the light of the above statements, choose the most appropriate answer from the options given below: