The line $\vec{r}=\vec{a} \times \lambda \vec{b}$ will not meet the plane $\vec{r} \cdot \vec{n}=q$, provided:
Answer & explanation
Correct answer: option 3
We must have
$\vec{b} . \vec{n}=0$ and $\vec{a} . \vec{n} \neq q$
Hence (3) is correct answer.