Which is not the correct statement about the chemistry of 3d and 4f series elements

Options

A. 3d-elements show more oxidation statesthan 4f-series elements ?
B. The energy difference between 3d and 4s orbitals is very little
C. Europium (II) is more stable than Ce(II)
D. The paramagnetic character in 3d -series elements increases from scandium to copper.

Explanation

The paramagnetic character is 3d series elements first increases from Sc to Mn as the number of unpaired electrons increases and then decreases as the number of unpaired electrons decreases from Fe to Cu.