If, $\vec a,\vec b,\vec c,\vec d$ are any four vectors, then $(\vec a×\vec b) × (\vec c×\vec d)$ is a vector
Answer & explanation
Correct answer: option 3
Clearly $(\vec a×\vec b) × (\vec c×\vec d)$ is perpendicular to both $\vec a×\vec b$ and $\vec c×\vec d$.
Hence, $(\vec a×\vec b) × (\vec c×\vec d)$ is equally inclined to both $\vec a×\vec b$ and $\vec c×\vec d$.