Which of the following hormones is a polypeptide?

The name 'second messenger' is given to

What does the given diagram of enzyme action represent?

Which of the following statements are applicable to hormones?
$I -$ Neural messengers
$II -$ Intercellular messengers
$III -$ Produced in trace amounts
$IV -$ Nutrient chemicals
$V -$ Released into the blood after production.

$I. ACTH$,$II. GH$,$III. MSH$,$IV. FSH$,$V. LH$,$VI. Oxytocin$. Which of the above hormones are polypeptide in nature?

Identify $A, B$ and $C$ in the diagrammatic representation of the mechanism of hormone action.
Select the correct option from the following: