Geometry

Question Analysis：
Tests ability to distinguish between properties that prove vs. describe a parallelogram.
The focus is filtering out the condition that isn’t sufficient on its own.

Key Concept Explanation:
The property about congruent diagonals is true for rectangles, not for all parallelograms.

Step-by-Step Solution：
A, B, C – All are valid parallelogram conditions.
D – Congruent diagonals may suggest a rectangle, but don’t guarantee it’s a parallelogr...