Which one of the following is now being commercially produced by biotechnological procedures?

In what form is human insulin synthesized,and what does it contain?

$\alpha-1$ antitrypsin is used to treat which disease?

With regard to insulin,choose the correct options.
$(a)$ $C$-peptide is not present in mature insulin.
$(b)$ The insulin produced by $rDNA$ technology has $C$-peptide.
$(c)$ The pro-insulin has $C$-peptide.
$(d)$ $A$-peptide and $B$-peptide of insulin are interconnected by disulphide bridges.
Choose the correct answer from the options given below.

Name of the drug used in cancer treatment produced by using biotechnology is:

The vaccine of Hepatitis-$B$ is a