Either a square or a rectangle.
A quadrilateral is a plane figure with four straight sides and does not necessarily have any congruent angles. Some quadrilaterals such as, squares, rectangles, rhombuses, and parallelograms do have...
A quadrilateral has four interior angles. It may have two, three, four, or none of them congruent.
rectangle
A parallelogram. A square or rectangle would also technically fit this description.
Rectangles or squares; both of these have only right angles, so all the angles are congruent.