Consider the following statements about insulin

$I$. Human insulin is made-up of $51$ amino acids arranged in two polypeptide chains

$II$. The two polypeptide chains are interconnected by two disulphide bridges

$III$. In mammals including humans, insulin is synthesized as a pro-hormone, which contains an extra stretch called the Cpeptide

$IV$. $C-$peptide is not present in the mature insulin

Which of the statements given above are correct?

• A

  $I$, $II$ and $III$

• B

  $I$, $III$ and $IV$

• C

  $II$, $III$ and $IV$

• D

  $I$, $II$, $III$ and $IV$