geometry
posted by Kate .
Quadrilateral QRST has two pairs of congruent sides, but it is not a parallelogram. What figure is it? What further condition would it have to satisfy to be a parallelogram?
A. The figure is a square. To be a parallelogram, it would have to have pairs of opposite congruent sides, not just congruent sides.
B. The figure is a rectangle. To be a parallelogram, it would have to have pairs of opposite congruent angles, not just congruent sides.
C. The figure is a kite. To be a parallelogram, it would have to have pairs of opposite congruent sides, not just congruent sides.
D. The figure is a square. To be a parallelogram, it would have to have pairs of opposite congruent angles, not just congruent sides.

How does A differ from D? Answer seems to be B, but the reasoning does not seem to fit. A square is a specific type of rectangle.
http://www.algebralab.org/lessons/lesson.aspx?file=Geometry_QuadrilateralsSpecialCharactieristics.xml