What is a counterexample for the

Question

following conjecture? If a
counterexample does not exist,
choose not possible.
Conjecture: All quadrilaterals are
rectangles.
(1 point)
A trapezoid is a
quadrilateral and it is not
a rectangle.
All quadrilaterals are not
rectangles.
A triangle is not a
quadrilateral, and it is not
a rectangle.
not possible

Answer 1

A counterexample for the conjecture that all quadrilaterals are rectangles is a square. A square is a quadrilateral, but it is not a rectangle.