Which element among the following is ferromagnetic?

The spin-only magnetic moment value of $M^{3+}$ ion (in gaseous state) from the pairs $Cr^{3+}/Cr^{2+}$,$Mn^{3+}/Mn^{2+}$,$Fe^{3+}/Fe^{2+}$,and $Co^{3+}/Co^{2+}$ that has a negative standard electrode potential,is $B.M.$ (Nearest integer).

Given below are two statements:
Statement $I$: $Cr^{2+}$ is oxidising and $Mn^{3+}$ is reducing in nature.
Statement $II$: $Sc^{3+}$ compounds are repelled by the applied magnetic field.
In the light of the above statements,choose the most appropriate answer from the options given below:

Assertion : Transition metals show variable valency.
Reason : Transition metals have a large energy difference between the $ns^2$ and $(n-1)d$ electrons.

Which of the following elements exhibits ferromagnetic properties?

The second and third rows of transition elements resemble each other much more than they resemble the first row. Explain why?