Arun
Last Activity: 7 Years ago
Dear student
When dot product is zero implies the two vectors are perpendicular. When cross product is zero implies the two vectors are parallel. So, the question is when two vectors are both perpendicular and parallel to each other? The answer is when at least one of them is trivial that is zero vector
Hence option D is correct.
Regards
Arun (askIITians forum expert)