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

Of the following outer electronic configurations of atoms,which one achieves the highest oxidation state?

Addition of non-metals like $B$ and $C$ to the interstitial sites of a transition metal results in the metal becoming:

$A$ copper coin was electroplated with $Zn$ and then heated at high temperature until there is a change in colour. What will be the resulting colour?

Transition elements are named transition elements because their characters are

Match the properties given in List-$I$ with the metals given in List-$II$:

List-$I$ (Property)	List-$II$ (Metal)
$(A)$ Element that can show $+8$ oxidation state	$(1)$ $Mn$
$(B)$ $3d$ series element that can show up to $+7$ oxidation state	$(2)$ $Cr$
$(C)$ $3d$ series element with maximum melting point	$(3)$ $Os$
	$(4)$ $Fe$