The products A and B in the following reactions, respectively are

$\mathrm{A} \stackrel{\mathrm{Ag}-\mathrm{NO}_2}{\longleftrightarrow} \mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{Br} \xrightarrow{\mathrm{AgCN}} \mathrm{B}$

The structure of the major product formed in the following reaction is :

Given below are two statements:

Statement I: The conversion proceeds well in the less polar medium.

$$\mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{Cl} \xrightarrow{\mathrm{HO}^{-}} \mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{OH}+\mathrm{Cl}^{(-)}$$

Statement II: The conversion proceeds well in the more polar medium.

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

Following are the four molecules "P", "Q", "R" and "S".

Which one among the four molecules will react with $\mathrm{H}-\mathrm{Br}_{(\mathrm{aq})}$ at the fastest rate?