Which element from the following exhibits the highest number of various different possible oxidation states?

Consider $|x|$ as the difference in oxidation states of Mn in the highest manganese fluoride and the highest manganese oxide. The ions with $|x|$ number of unpaired electrons from the following are: $A$. $Sc^{3+}$ $B$. $Zn^{2+}$ $C$. $V^{2+}$ $D$. $Fe^{2+}$ $E$. $Co^{2+}$ Choose the correct answer from the options given below:

Which of the following metals forms more than one chloride?

Many transition metals form interstitial compounds. The characteristics of these interstitial compounds are:
$I$. They have high melting points,higher than those of pure metals.
$II$. They are very hard.
$III$. They retain metallic conductivity.
$IV$. They are chemically more reactive than the pure metals.

Match the following:

List-$I$ (Transition metal,$M$)	List-$II$ ($E_{M^{2+}/ M}^{\ominus}$ in $V$)
$A$. $Ni$	$I$. $-1.18$
$B$. $Mn$	$II$. $-0.91$
$C$. $Fe$	$III$. $-0.25$
$D$. $Cr$	$IV$. $-0.44$

The correct answer is

Define transition elements and inner transition elements.