In Gene cloning:

Ethidium bromide stained agarose gel is exposed to $.......,$ to observe $\text{DNA}$ as bright orange coloured bands.

Which of the following statements are correct with respect to $DNA$ separation, isolation and visualization?
$A$. The cutting of $DNA$ is done by molecular scissors.
$B$. The $DNA$ fragments separate according to their size in an agarose gel, upon electrophoresis.
$C$. The separated $DNA$ fragments can be seen without staining when exposed to $UV$ light.
$D$. The separated $DNA$ fragments, when stained with ethidium bromide, can be seen in visible light.
Choose the correct answer from the options given below:

When was the first extra $DNA$ fragment successfully inoculated into $E. coli$ using a plasmid?

$I.$ In the process of recombinant $DNA$ technology,after several treatments,the purified $DNA$ is precipitated by adding chilled ethanol.
$II.$ The bacterial,plant,or animal cell is broken down by enzymes to release $DNA$,along with $RNA$,proteins,polysaccharides,and lipids.
Choose the correct option for the above statements.

$I. ... A...$ is the ability of a cell to take up foreign $DNA$.
$II.$ The cell is treated with a specific concentration of a divalent cation such as $... B...$ to increase the pore size in the cell wall.
$III.$ In $...C...$ method,recombinant $DNA$ is directly injected into the nucleus of an animal cell.
The most appropriate option regarding $A, B$ and $C$ is: