Answer
$2H_2+CO\rightarrow CH_3OH$
Work Step by Step
We know that $H_2$ and $CO$ are combining to make $CH_3OH$.
Each molecule of $CH_3OH$ output contains 4 of $H$ and one each of $O$ and $C$. In order to balance, the input must be 2 of $H_2$ and one of $CO$.
