Which among the following elements has a completely filled $4d$ orbital?

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

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).

Which of the following rules must be followed to form an alloy?

In comparison of ferrous salts,ferric salts are

Match the following elements in List-$I$ with their respective groups in List-$II$.

List-$I$ (Elements)	List-$II$ (Group)
$A$. $Mn, Tc, Re$	$IV$. $7$
$B$. $Zn, Cd, Hg$	$I$. $12$
$C$. $Ti, Zr, Hf$	$II$. $4$
$D$. $Ga, In, Tl$	$V$. $13$

The correct answer is: