What are parallel lines?

Lines that run side by side at equal distance

The governing geometric concept is parallelism. Two lines are parallel when they lie in the same plane and maintain a constant distance from each other; if extended indefinitely, they do not meet. Railway tracks are a familiar visual example, although their apparent meeting in the distance is caused by perspective. Option A is correct because it states the essential property: the lines run alongside one another without changing their separation. Option B describes intersecting or meeting lines, not parallel lines. Option C confuses a line relationship with a shape, since parallel lines may be straight but are not defined as round. Option D is unrelated because visibility has nothing to do with whether lines are parallel. Equal spacing and non-intersection are the key features to remember.

This is a Class 9 Art Education question. Chapter: Elements of Art. Topic: Line.