Which of the following vitamins is not fat-soluble?

Identify the natural source of ascorbic acid from the following.

The metal ion present in vitamin $B_{12}$ is

Vitamin $A$ is present in

Which of the following biomolecules contains a non-transition metal ion?

Which of the following statements are correct?
$a$. Deficiency of vitamin $K$ results in increased blood clotting time.
$b$. The sources of vitamin $B_2$ are milk and liver.
$c$. Hexapeptide has six peptide bonds.
$d$. Improper functioning of adrenal cortex results in hypoglycemia.