The main reason for larger number of oxidation states exhibited by the actinoids than the corresponding lanthanoids, is :-

Question

( A ) Lesser energy difference between 5f and 6d orbitals than between 4f and 5d orbitals
( B ) Larger atomic size of actinoids than the lanthanoids
( C ) More energy difference between 5f and 6d orbitals than between 4f and 5d orbitals
( D ) Greater reactive nature of the actinoids and the lanthanoids