Which of the following methods(s) is used to introduce foreign $DNA$ into host cells?

In gel electrophoresis, the separated $DNA$ fragments are visualized after staining the $DNA$ with $…A…$ followed by exposure to $…B…$

Here $A$ and $B$ refers to

Select the correct pair :

Which one of the following palindromic base sequences in $DNA$ can be easily cut at about the middle by some particular restriction enzyme?

$I. … A…$ is the ability of a cell to take up foreign $DNA$

$II.$ The cell is treated with specific concentration of a divalent cation such as $… B…$ to increase pore size in cell wall

$III. $In $…C…$ method recombinant $DNA$ is directly injected into the nucleus of an animal cell

The most appropriate option regarding $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$ is