Dihydrogen can be prepared on commercial scale by different methods. In its preparation by the action of steam on hydrocarbons, a mixture of $CO$ and $H_2$gas is formed. It is known as

The correct option is C Water gas
The mixture of $CO$ and $H_2$ is called water gas. It is also called synthesis gas or 'syngas'. Producer gas is a mixture of $CO,C{O}_2,H_2$ and$N_2$.

Hence, options (A) and (B) are correct.