The incorrect statement for lanthanides among the following statements is :
A. 4f and 5d orbitals are so close in energy that I t is very difficult to locate the exact position of electrons in lanthanides
B. most common stable oxidation state is +3
C. tripositive lanthanide ions have characteristic color depending on nature of group with which they combine to form compounds
D. some lanthanide ions absorb either in infrared or ultraviolet region of electromagnetic spectrum
