Which information is sufficient to show that a parallelogram is a rectangle?

A. The diagonals bisect each other.

B. The diagonals are congruent.

C. The diagonals are congruent and perpendicular.

D. The diagonals bisect each other and are perpendicular.

The answer is B.

B. The diagonals are congruent.

A. The diagonals of any rhombus bisect each other, but that does not prove it is a rectangle.

B. The quadrilateral is a parallelogram, and the diagonals are congruent. It must be a rectangle.

C. The diagonals are congruent and perpendicular in any rhombus, but that does not make it a rectangle.

D. This proves a rhombus, but not necessarily a rectangle.