What is the main difference between visual hierarchy by line and value hierarchy?

Line hierarchy is made by line weight, value hierarchy by light and dark

The governing concept is hierarchy: both systems organize the viewer’s attention, but they use different visual variables. Line hierarchy is created through differences in thickness, darkness, continuity, sharpness, or prominence of marks. Value hierarchy is created through a sequence or contrast of light, middle, and dark areas. Option A is correct because it separates the tools while recognizing their shared purpose. The two hierarchies can cooperate—for example, a dark outline and a strong value contrast may emphasize the same figure—but they are not identical. Options B and C are meaningless or false, and option D is poorly stated and does not identify the actual difference. Accurate analysis names the visual means used to control emphasis.

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