Which of the following is a vital stain?

Column-$I$ represents the organelle and Column-$II$ represents its structure. Select the correct option:

Column-$I$	Column-$II$
$(A)$ Mitochondria	$(i)$ Single membrane-bound structure
$(B)$ Lysosome	$(ii)$ Non-membrane-bound structure
$(C)$ Nucleolus	$(iii)$ Double membrane-bound structure

In the given figure,what do $a$ and $b$ represent respectively?

Which option correctly identifies the parts labeled $a$ and $b$ in the given figure?

$S$ - Statement: The nucleolus is the regulatory center for various activities occurring in the cell.
$R$ - Reason: Rudolf Virchow coined the term 'cell'.

Which of the following pairs of organelles does not contain $DNA$?