Geometry

Question Analysis:  
This question targets understanding rhombus properties.  
The main focus is on necessary proof conditions.

Key Concept Explanation:  
Rhombus = all sides congruent.

Step-by-Step Solution:  
Use distance formula on all sides and show they are equal.

Option Analysis:  
- A. Rectangle condition, not rhombus.  
- B. Square or rectangle, not rhombus.  
- C. Correct. Sides congruent def...