Larger number of oxidation states are exhibited by the actinoids then those by the lanthanoids, the main reason being

Options

A. 4f -orbitals more diffused than the 5 f-orbitals
B. lesser energy difference between 5 f and 6d than between 4 f and 5 d-orbitals
C. more energy difference between 5f and 6d than between 4f and 5d-orbitals
D. more reactive nature of the actinoids than the lanthaniods

Answer

B