The atomic radill of alkali meals (M) lie in the order `Li lt Na lt K lt Rb,` but the radii of `M^(+)` ions in aqueous solution lie in the reverse order `Li^(+) gt Na^(+) gt Rb^(+).` What is the reason for this reverse order (on going from Li to Rb)
A. Gradual increase in ionisation energy.
B. Increasing weakness of metallic bond.
C. Omcreasomg electropositive character.
D. Decreasing degree of hydration