Which among the following halides will generate the most stable carbocation in the nucleophilic substitution reaction?

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