parallel (option A)
Explanation:
Parallel lines are lines that are always same distance apart. They do not intersect
Perpendicular lines are lines that intersect at angle 90 degrees
From the diagram:
AB is parallel to EF
EF is parallel to GH
AB is also parallel to CD
CD is parallel to GH
Since EF is parallel to both AB and GH.
Hence, AB is parallel to GH
So, AB and GH are parallel
