A student makes the following conjecture: “If a quadrilateral is a rectangle, then it must be a parallelogram.” If someone doesn’t believe this conjecture is true, which of the following would be necessary to have a counterexample to it?
A.
A rectangle that is a parallelogram
B.
A parallelogram that is a rectangle
C.
A rectangle that is not a parallelogram
D.
A parallelogram that is not a rectangle
