If a line segment $AB$ is parallel to the line $XY$, its orthogonal projection $A'B'$ on $XY$ equals —

Question

Accepted Answer

$AB$

Answer

$0$

Answer

$\frac{1}{2} AB$

Answer

$2 AB$

If a line segment ABABAB is parallel to the line XYXYXY, its orthogonal projection A′B′A'B'A′B′ on XYXYXY equals —