Find the unit vector in the direction of the vector $ \overrightarrow a = \hat i + \hat j + 2\hat k$ .

Question

$\begin{array}{1 1}(A) \large\frac{1}{6}\hat i+\large\frac{1}{6}\hat j+\large\frac{1}{6}\hat k \\(B) 6\hat i+6\hat j+12 \hat k \\(C) \large\frac{1}{\sqrt 6}\hat i+\large\frac{1}{\sqrt 6}\hat j+\large\frac{2}{\sqrt 6}\hat k \\ (D) \sqrt 6\hat i+\sqrt 6\hat j+\sqrt 6 \hat k \end{array} $