In which condition can a broken line be more effective than a continuous line?

When instability, suggestion, or incompleteness must be shown

A broken line creates intervals, pauses, and visual gaps. Those interruptions can be used intentionally to suggest incompleteness, uncertainty, movement, a lightly indicated edge, or an object that is partly hidden. For that reason, option A is correct: the discontinuity communicates something that a firm uninterrupted contour may not communicate as effectively. A broken line can also invite the viewer to mentally complete a form, so it is useful when suggestion is preferred over full description. Option B calls for a continuous, clearly defined boundary, while C is not a specific reason to break a line and D directly conflicts with the presence of gaps. The choice should serve the subject and composition rather than be treated as an automatic rule.

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