Which shape could be a type of quadrilateral with at least one pair of parallel sides?

A quadrilateral is defined as a polygon with four sides, and there are several types of quadrilaterals, each with different properties. A trapezoid, in particular, is characterized by having at least one pair of parallel sides. This definition aligns perfectly with the question's requirement.

A trapezoid can take various forms, including an isosceles trapezoid, where the non-parallel sides are equal, and an irregular trapezoid, which does not maintain any form of symmetry or equal lengths among its sides. The presence of at least one pair of parallel sides distinguishes trapezoids from other quadrilaterals like rectangles and squares, which have more restrictive conditions.

In contrast, while squares and rectangles are technically quadrilaterals and do have parallel sides, they are both specific cases of trapezoids with additional properties (like all sides equal in the case of squares, or opposite sides equal in rectangles). A triangle does not qualify as a quadrilateral at all, as it has only three sides. Thus, the trapezoid stands out as the correct type of quadrilateral that meets the specified criterion.