Draw the orbital diagram of carbonyl group showing the $\mathrm{\pi }$ bond. 

${\mathrm{CH}}_3\mathrm{OH}\stackrel{ \left[\mathrm{O}\right] }{\to }\left[\mathrm{A}\right]\stackrel{{\mathrm{CH}}_3 \mathrm{MgI} }{\to }\left[\mathrm{B}\right]\stackrel{ {\mathrm{H}}_2\mathrm{O} }{\to }\left[\mathrm{C}\right]$

Write the chemical formula of $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$ in the above reaction sequence.