Which of the following elements are analogous to the lanthanides?

Identify the correct actinide series from the following.

What is the correct order of ionic radii for the $+3$ oxidation state in $Ce, La, Pm,$ and $Yb$?

The ionic radius of $La^{3+}$ is $1.06 \ \mathop{A}\limits^o$. Which of the following is the closest value for the ionic radius of $Lu^{3+}$ in $\mathop{A}\limits^o$? $(Lu = 71, La = 57)$

The lanthanide contraction relates to

Which of the following statements are correct?
$I$. $P$ has the least negative electron gain enthalpy among $P, S, Cl$, and $F$.
$II$. In $Eu$ and $Yb$, lanthanoid contraction is not observed.
$III$. $Ce(OH)_3$ is the most basic among lanthanoid hydroxides.
$IV$. The radii of $Na$ and $Na^+$ are $95 \ pm$ and $186 \ pm$ respectively.