If the points whose position vectors are $2 \hat i+\hat j+\hat k, 6 \hat i-\hat j+2 \hat k$ and $14\hat i-5 \hat j+p \hat k$ are collinear, then the value of p is

Question

$$\begin {array} {1 1} (a)\;2 & \quad (b)\;4 \\ (c)\;6 & \quad (d)\;8 \end {array}$$