Why can using only a dark outline weaken depth in an exam drawing?

Correct answer: Because all edges begin to look equally important

A dark outline gives every boundary nearly the same strength. When the foreground, middle ground, and background all have equally heavy edges, the viewer receives fewer clues about distance. The picture may look flat because objects at different depths appear equally close and equally important. Depth is often clearer when the artist varies line weight, darkness, sharpness, and detail according to position and lighting.

Option A is correct because uniform dark outlines make all edges appear equally important. A dark line is not always wrong; it can emphasize a nearby form or an important contour. Lines do relate to depth, and an outline does not increase colour simply by being dark. In a drawing, stronger and clearer lines may describe nearer forms, while lighter, thinner, broken, or less detailed lines can help push distant forms back.