If $\overrightarrow{a}=\overrightarrow{i}-\overrightarrow{2j}+\overrightarrow{3k}$ and $\overrightarrow{b}=\overrightarrow{3i}+\overrightarrow{j}+\overrightarrow{2k}$ then a unit vector perpendicular to $\overrightarrow{a}$ and $\overrightarrow{b}$ is

Question

$$\begin{array}{1 1}(1)\large\frac{\overrightarrow{i}+\overrightarrow{j}+\overrightarrow{k}}{\sqrt{3}}&(2)\large\frac{\overrightarrow{i}-\overrightarrow{j}+\overrightarrow{k}}{\sqrt{3}}\\(3)\large\frac{-\overrightarrow{i}+\overrightarrow{j}+\overrightarrow{2k}}{\sqrt{3}}&(4)\large\frac{\overrightarrow{i}-\overrightarrow{j}-\overrightarrow{k}}{\sqrt{3}}\end{array}$$