Which among the following has lowest boiling point?

Which from following is obtained by hydroboration - oxidation of propene?

Identify the reagent 'R' used in the following reaction
$\text{C}_6\text{H}_5\text{COCl} \xrightarrow{\large{\text{R}}} \text{C}_6\text{H}_5\text{CHO} + \text{HCl}$

Identify the product 'B' in the following reaction
$\text{Isopropyl cyanide} \xrightarrow{\large{\text{SnCl}_2, \text{HCl}}} \text{A} \xrightarrow{\large{\text{H}_3\text{O}^+}} \text{B} + \text{NH}_4\text{Cl}$