Which of the following is not required for $PCR$?

Main steps in the formation of Recombinant $DNA$ are given below. Arrange these steps in a correct sequence.
$A$. Insertion of recombinant $DNA$ into the host cell
$B$. Cutting of $DNA$ at specific location by restriction enzyme
$C$. Isolation of desired $DNA$ fragment
$D$. Amplification of gene of interest using $PCR$
Choose the correct answer from the options given below:

Separation of $\text{DNA}$ fragments is done by a technique known as :

$PCR$ is used for:

Given below are two statements:
Statement $I:$ The $\text{DNA}$ fragments extracted from gel electrophoresis can be used in the construction of recombinant $\text{DNA}$.
Statement $II:$ Smaller size $\text{DNA}$ fragments are observed near the anode while larger fragments are found near the wells in an agarose gel.
In the light of the above statements,choose the most appropriate answer from the options given below:

The different basic steps of genetic engineering are given below randomly:
$I.$ Identification of $DNA$ with desirable genes
$II.$ Gene transfer
$III.$ Maintenance of $DNA$ in host and gene cloning
$IV.$ Introduction of $DNA$ into host to form recombinant $DNA$
Which of the following represents the correct sequence of steps?