How many elements are there in the $4f$ series?

Which orbitals,$4f$ or $5f$,are more capable of participating in bond formation?

Match the properties given in List-$I$ with the elements given in List-$II$:

List-$I$ (Property)	List-$II$ (Element)
$(A)$ Lanthanoid showing $+4$ oxidation state	$(i)$ $Pm$
$(B)$ Lanthanoid showing $+2$ oxidation state	$(ii)$ $Ce$
$(C)$ Radioactive lanthanoid	$(iii)$ $Lu$
$(D)$ Lanthanoid with $4f^7$ configuration in $+3$ state	$(iv)$ $Eu$
$(E)$ Lanthanoid with $4f^{14}$ configuration in $+3$ state	$(v)$ $Gd$
-	$(vi)$ $Dy$

Assertion : Magnetic moment values of actinides are lesser than the theoretically predicted values.
Reason : Actinide elements are strongly paramagnetic.

$Ce - 58$ is a member of

Which among the following is an actinoid element?