A square.
paralellogram
The answer is parallel because a parallel has 2 sided figure.
A diamond has 2 sets of parallel sides.
A trapezoid only has only two parallel sides.
rhombus
Trapezoid
A hexagon is any two-dimensional polygon with six sides and six vertices. If it is a regular hexagon, then opposite sides are parallel and each of the angles equals 120 degrees. The six interior angles then add up to 720 degrees
An impossible figure
trapezium
A trapezoid is a four sided figure with at least one set of parallel sides
A triangle. It has only three sides!
rhombus