Which bacterium is commonly used in genetic engineering?

$I.$ Bacteriophages are $...A...$ infecting $...B....$
$II. ...C...$ are hybrid vectors derived from plasmids which contain $cos$ site of $\lambda$ phage.
$A, B$ and $C$ in above statements refer to:

Match the following columns:

Column-$I$	Column-$II$
$(a) \ Cla \ I$	$(1) \ \text{Antibiotic resistance gene}$
$(b) \ pBR322$	$(2) \ \text{Origin of replication}$
$(c) \ tet^R$	$(3) \ \text{Restriction enzyme}$
$(d) \ ori$	$(4) \ \text{Plasmid}$

In $Ti$-plasmid, which of the following is removed:

The enzyme known as restriction endonuclease:

The enzyme restriction endonuclease: