Answer: parallelogram
Reason:
Any square and rectangle is automatically a parallelogram, but not the other way around. This places the parallelogram at the top of the food chain so to speak. It's the more generalized shape. Any parallelogram has two opposite sides that are parallel.
A trapezoid is somewhat halfway in the door. It has exactly one pair of opposite parallel sides, while the other pair of opposite sides aren't parallel. The trapezoid is not part of the parallelogram tree. It's on its own separate island.
Side note: Any square is a rectangle, but not vice versa.