Answer is : C. (2/7 i - 3/7 j + 6/7 k)
Tip – A vector in the direction of another vector ai + bj + ck is given by λ(ai + bj + ck) and the unit vector is given by
So, a vector parallel to vector a = 2i - 3j + 6k is given by λ(2i - 3j + 6k) where λ is an arbitrary constant.
Now, \(|\overset{\rightarrow}{a}|\) = \(\sqrt{2^2+3^2+6^2}\) = 7
Hence, the required unit vector