# The equation of the plane through the point $(1,2,-1)$ and $\perp$ to the line of intersection of the planes $\overrightarrow r.(3\hat i-\hat j+\hat k)=1$ and $\overrightarrow r.(\hat i+4\hat j-2\hat k)=2$ is?
$\begin{array}{1 1} (a)\:\overrightarrow r.(2\hat i+7\hat j-13\hat k)=1\:\qquad\:(b)\:\overrightarrow r.(2\hat i-7\hat j-13\hat k)=1\:\qquad\:(c)\:\overrightarrow r.(2\hat i+7\hat j+13\hat k)=0\:\qquad\:(d)\overrightarrow r.(-2\hat i+7\hat j-13\hat k)=1 \end{array}$