The lanthanide ion having four unpaired electrons is (Given: Atomic numbers of Ce=58, Nd=60, Tb=65 and Ho=67 )

The lanthanide ion having four unpaired electrons is (Given : Atomic numbers of $\displaystyle \mathrm{Ce}=58$, $\displaystyle \mathrm{Nd}=60, \mathrm{~Tb}=65$ and $\displaystyle \mathrm{Ho}=67$ )