Geometry

Question Analysis:
This question challenges your ability to eliminate non-sufficient conditions.
The main focus is identifying angle facts that are true but not sufficient for a proof.

Key Concept Explanation:
Some angle conditions (like A or B) are too general
Condition E is sufficient to prove a parallelogram
D is a true and sufficient property
C is true for rectangles or squares, special type of parallelogram.

Step-by-Step Solution:
A ❌: 360° is true for all quadrilaterals – not a proof → not sufficient
B ❌: One pair of opposite angles isn’t enough – both are needed
C ✅: All angles congruent = rectangle/square, special type of parallelogram.
D ✅: If each pair of adjacent angles is supplem...