Question

Which of the following best describes a plane?
A. The edge of a desk
B. A curve in a road
C. The point of intersection of two walls
D. The surface of a flat table

Answer 1

A).  The edge of a desk is probably a rectangle.

B).  A curve in the road is a curved line.

C).  Two walls intersect in a line.  Not a point, and not a plane.

D).  The surface of a flat table doesn't 'describe' a plane, but
        it's an example of a plane.

Answer 2

A. The edge of a desk
B. A curve in a road
C. The point of intersection of two walls
D. The surface of a flat table

Think about it like this: A flat grassland plane. 
It is FLAT
Plane describers flat.