Which line can make a picture feel less still and more active?

Diagonal line

The governing concept is that line direction influences the sense of movement and energy in a composition. A diagonal line is visually unstable compared with a level horizontal or upright vertical line because it appears to lean, rise, fall, or move across the picture. This directional tension makes the scene feel more active and can suggest action, speed, or change. Therefore option A is correct. Horizontal lines commonly communicate rest, calm, and stability, while vertical lines often suggest height, strength, or firmness. Curved lines can also express movement in some contexts, but the standard elementary-art association for making a picture feel less still is the diagonal line. The effect depends on placement and context, yet A is the clearest expected answer.

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