Geometry

Question Analysis:
This conceptual question requires recognizing invalid angle configurations for parallelograms.

Key Concept Explanation:
Valid parallelogram angle configurations must satisfy:
Opposite angles equal
Adjacent angles supplementary
Total sum of 360°

Step-by-Step Solution:
Check each option:
A) Valid: 70°+110°=180°, opposites equal
B) Valid: 85°+95°=180°, opposites equal
C) Valid: Rectangle case
D) Invalid: 60°+100°≠180° and 60°+140°≠180°

Common Mistakes:
Overlooking that both pairs of adjacent angles must be checked
Assuming all op...