$PCR$ is used to:

Match the following:-

Column-$I$	Column-$II$
$(A)$ $\text{YAC}$	$(I)$ Separation of $\text{DNA}$ fragments
$(B)$ $\text{Hind II}$	$(II)$ Yeast
$(C)$ Gel electrophoresis	$(III)$ First restriction endonuclease
$(D)$ Heterologous host	$(IV)$ Recombinant protein

Assertion $:-$ The tumor inducing $(Ti)$ plasmid of $Agrobacterium$ $tumefaciens$ has now been modified into a cloning vector.
Reason $:-$ Retroviruses have been disarmed and are now used to deliver genes into animal cells.

Match the following columns:

Column $I$	Column $II$
$A$. Recombinant $DNA$	$1$. Sea weeds
$B$. Gel electrophoresis	$2$. $DNA$ staining
$C$. Ethidium bromide	$3$. Plasmid $DNA$ that has incorporated human $DNA$
$D$. Agarose	$4$. Process by which $DNA$ fragments are separated based on their size

Choose the incorrect option $-$

$A$: $cDNA$ libraries are important to scientists in human genomics.
$R$: $cDNA$ is a synthetic type of $DNA$ generated from $mRNA$.