Geometry

Question Analysis:
This question involves classifying a parallelogram as a rhombus.
The main focus is on diagonal properties.

Key Concept Explanation:
A rhombus has diagonals that are perpendicular to each other.

Step-by-Step Solution:
A: Diagonal congruence → rectangle
B: Diagonal perpendicularity → rhombus
C: One right angle → rectangle
D: All parallelograms have parallel opposite sides

Option Analysis:
On...