The position vector of a point lying on the line joining the points whose positions vectors are $\hat i+\hat j-\hat k$ and $\hat i- \hat j +\hat k$ is :

Question

$$\begin {array} {1 1} (a)\;\hat {j} & \quad (b)\;\hat {i}\\ (c)\;\hat {k} & \quad (d)\;\overrightarrow {0}\end {array}$$