Answer:
Option B
Explanation:
Let A(1, 0, 1), B(0, 2,2) andc (3, 3, 0) be the given points, then
$\vec{AB}=-\hat{i}+2\hat{j}+2\hat{k}$, $\vec{BC}=3\hat{i}+\hat{j}-2\hat{k}$
$\vec{AB}\times\vec{BC}=\begin{vmatrix}\hat{i} & \hat{j} & \hat{k} \\-1 & 2 & 1 \\ 3 & 1 & -2\end{vmatrix}= -5\hat{i}+\hat{j}-7\hat{k}$
.'. unit vector $\perp$ to the Plane: ABC
= $\pm\frac{1}{5\sqrt{3}}(-5\hat{i}+\hat{j}-7\hat{k})$
