Product. The product of the given reaction is:

Compounds $\mathrm{A}$ and$\mathrm{C}$ in the following reaction are 

${\mathrm{CH}}_3\mathrm{CHO}\underset{\left(\mathrm{ii}\right){\mathrm{H}}_2\mathrm{O}}{\overset{\left(\mathrm{i}\right){\mathrm{CH}}_3\mathrm{MgBr}}{\to }}\left(\mathrm{A}\right)\stackrel{{\mathrm{H}}_2{\mathrm{SO}}_4,∆}{\to }\left(\mathrm{B}\right)\stackrel{\mathrm{Hydroboration} \mathrm{oxidation}}{\to }\left(\mathrm{C}\right)$