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

Question

( A ) lesser energy difference between 5f and 6d than between 4f and 5d orbitals
( B ) more reactive nature of the actinoids than the lanthanoids
( C ) 4f orbitals more diffused than the 5f orbitals
( D ) more energy difference between 5f and 6d than between 4f and 5d orbitals