Geometry

Question Analysis:
This question tests understanding of diagonal properties for classification.
The main focus is interpreting the implications of perpendicular but unequal diagonals.

Key Concept Explanation:
Perpendicular diagonals: Occurs in rhombuses and squares
Unequal diagonals: Eliminates squares (must have equal diagonals)
Rectangles: Have equal diagonals that aren't perpendicular
Therefore, only rhombuses fit both conditions

Step-by-Step Solution:
Eliminate A (rectangle diagonals aren't perpendicular)
Eliminate C (square diagonals must be equal)
Eliminate D (square is eliminated by "not equal" condition)
Confirm B is only remaining valid option

Common Mistakes:
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