Which statement best describes a parallelogram?

• A. A rectangle with equal opposite sides.
• B. A circle with four vertices.
• C. A closed four-sided figure in which the opposite sides are parallel.
• D. A triangle with two parallel sides.

Answer: (C)

Parallelograms are four‑sided figures where opposite sides run parallel to each other. That single property defines the shape and leads to other features like opposite sides being equal and the diagonals bisecting each other. The statement that describes a closed four‑sided figure with opposite sides parallel matches this definition precisely, making it the best description. Describing it as a rectangle with equal opposite sides is too restrictive, since a parallelogram need not have right angles. A circle with four vertices isn’t a polygon, and a triangle cannot have parallel sides because it only has three sides that meet.