$$ \text { From the following, the least stable structure is : } $$

Identify the correct statements.

A. Arginine and Tryptophan are essential amino acids.

B. Histidine does not contain heterocyclic ring in its structure.

C. Proline is a six membered cyclic ring amino acid.

D. Glycine does not have chiral centre.

E. Cysteine has characteristic feature of side chain as $\mathrm{MeS}-\mathrm{CH}_2-\mathrm{CH}_2-$.

Choose the correct answer from the options given below :

A hydrocarbon ' P ' $\left(\mathrm{C}_4 \mathrm{H}_8\right)$ on reaction with HCl gives an optically active compound ' Q ' $\left(\mathrm{C}_4 \mathrm{H}_9 \mathrm{Cl}\right)$ which on reaction with one mole of ammonia gives compound ' $\mathrm{R}^{\prime}\left(\mathrm{C}_4 \mathrm{H}_{11} \mathrm{~N}\right)$. ' $\mathrm{R}^{\prime}$ on diazotization followed by hydrolysis gives ' S '. Identify $\mathrm{P}, \mathrm{Q}, \mathrm{R}$ and S .

Given below are two statements :

Statement I : The number of pairs among $\left[\mathrm{SiO}_2, \mathrm{CO}_2\right],\left[\mathrm{SnO}, \mathrm{SnO}_2\right],\left[\mathrm{PbO}, \mathrm{PbO}_2\right]$ and $\left[\mathrm{GeO}, \mathrm{GeO}_2\right]$, which contain oxides that are both amphoteric is 2 .

Statement II : $\mathrm{BF}_3$ is an electron deficient molecule, can act as a Lewis acid, forms adduct with $\mathrm{NH}_3$ and has a trigonal planar geometry.

In the light of the above statements, choose the correct answer from the options given below :