Sinks of carbon monoxide $2CO+O_2\qquad \underrightarrow {soil}\qquad x$.$CO+3H_2\qquad\underrightarrow{soil}\qquad y+z$.The $y$ in the equation is

Question

$\begin{array}{1 1}(a)\;CH_3\\(b)\;CH_2\\(c)\;CH_4\\(d)\;CH_2^-\end{array}$