______ is prepared on a large scale from water gas.

The correct option is A Methanol
Methanol is prepared on a large scale from water gas.
Water gas is an equimolar mixture of $CO$ and $H_2$. Water gas is heated with hydrogen (2:1 ratio) in presence of catalyst to form methanol. The reaction for methanol preparation is as follow:
$\underset{\text{Water gas}}{CO+2H_2}\underset{{300}^{\circ }C,\text{200-300 atm}}{\overset{ZnO-C{r}_2{O}_3}{\to }}C{H}_{3}OH$