Answer:

A. Consecutive angles are congruent

Explanation:

This is a wrong condition. We must prove that a quadrilateral is a parallelogram if the Consecutive angles are supplementary.

Properties of a Parallelogram:

• Consecutive angles must be supplementary.
• Opposite angles are congruent.
• Diagonals bisect each other.
• Diagonals intersect.
• Opposite sides are congruent
• Both pair of opposite sides must be parallel.