Geometry

Question Analysis:
This question tests the fundamental definition of a parallelogram, focusing on the parallelism of opposite sides.

Key Concept Explanation:
A parallelogram is defined as a quadrilateral where both pairs of opposite sides are parallel and equal in length.

Step-by-Step Solution:
Option A is false because both pairs must be parallel.
Option B is correct (definition of a parallelogram).
Option C is false (diagonals bisect but are not necessarily perpendicular).
Option D is false (only rectangles, a subset of parallelograms, have right angles).

Common Mistakes...