Which of the following acids is a vitamin ?

Radius of the first excited state of Helium ion is given as : $\mathrm{a}_0 \rightarrow$ radius of first stationary state of hydrogen atom.

The IUPAC name of the following compound is :

Consider the following sequence of reactions :

Molar mass of the product formed $(\mathrm{A})$ is __________ $\mathrm{g} \mathrm{~mol}^{-1}$.