In which of the following properties do $Lanthanoids$ and $Actinoids$ show similarity?

The reason for the greater range of oxidation states in actinoids is attributed to:

The lanthanide contraction is responsible for the fact that

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$:
Assertion $A$: Size of $Bk^{3+}$ ion is less than $Np^{3+}$ ion.
Reason $R$: The above is a consequence of the lanthanoid contraction.
In the light of the above statements,choose the correct answer from the options given below:

From the list given below,the number of lanthanides which exhibit $+4$ oxidation state in their oxides is: $Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy$

The electronic configuration of Curium (Atomic number $96$) is