An organic compound contains $78 \%$ (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is : [Atomic wt. of $C$ is $12, H$ is 1$]$
(1) $\mathrm{CH}$
(2) $\mathrm{CH}_{2}$
(3) $\mathrm{CH}_{3}$
(4) $\mathrm{CH}_{4}$