Which element from the following is radioactive?

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

The correct statements among the following are:
$A$. $Mo(VI)$ and $W(VI)$ are less stable than $Cr(VI)$.
$B$. $Ce^{4+}$ and $Tb^{4+}$ are oxidants,while $Eu^{2+}$ and $Yb^{2+}$ are reductants.
$C$. $Cm$ and $Am$ have seven unpaired electrons.
$D$. Actinoid contraction is greater from element to element than lanthanoid contraction.
Choose the correct answer from the options given below:

If the electronic configuration of $M^{3+}$ is $[Xe] \ 4f^3$,then $M^{3+}$ is

Which of the following statements is $NOT$ incorrect?