More number of oxidation states are exhibited by the actinoids than by the lanthanoids. The main reason for this is
A. more energy difference between 5f and 6d orbitals than that between 4f and 5d-orbitals
B. lesser energy difference between 5f and 6d-orbitals than that between 4f and 5d-orbitals
C. greater metallic character of the lanthanides than that of the corresponding actinides
D. more active nature of the actinides.