When foreign $\text{DNA}$ is inserted into any vector,it results in inactivation of any marker gene. This is used for selection of $......\ :-$

Which of the following methods is used for the isolation of $DNA$?

Match List $I$ with List $II$:

List $I$	List $II$
a) Visualization of $DNA$ in gel electrophoresis	i) Chitinase
b) Precipitation of $DNA$	ii) Lysozyme
c) Breaking of cell wall of bacteria	iii) Chilled ethanol
d) Breaking of cell wall of fungus	iv) Ethidium bromide

Codes:

Which of the following statements is incorrect?

Study the given figure carefully and select the correct statements regarding this.
$I.$ It represents typical agarose gel electrophoresis showing differential migration of $DNA$ fragments.
$II.$ Lane $1$ contains undigested $DNA$ fragments.
$III.$ Lanes $2$ to $4$ contain digested $DNA$ fragments.
$IV.$ Smallest $DNA$ bands are present at $(A)$ position and largest $DNA$ bands are present at $(B)$ position.

Identify the correct statement.