The distance of a point (1, -1, 0) from the plane $\vec{r}. (3\hat{i}-2\hat{j}-6\hat{k})=4$ is :

$\frac{1}{7}$ $\frac{9}{7}$ $\frac{5}{7}$ $\frac{6}{7}$

$\frac{1}{7}$