For two variables $x$ and $y$ with the same mean the two regression lines are $x+2y-5=0$ $2x+3y-8=0$ and variance $(x)=12$ Then $\sigma_y$ is

Question

$\begin {array} {1 1} (A)\;4 & \quad (B)\;5 \\ (C)\;2 & \quad (D)\;None\: of \: these \end {array}$