A zigzag line can be useful for which effect?

Correct answer: Sharpness and break

The direct answer is B: sharpness and break. A line is not only a boundary; its direction and movement can communicate feeling. A zigzag line changes direction suddenly, so it looks pointed, energetic, restless, or broken. The reasoning is simple: repeated sharp turns create corners; corners suggest tension and force; therefore the line can show intensity or a broken movement. Option A, complete peace, is usually better suggested by calm horizontal or gently flowing lines, not sudden points. Option B is correct because the sharp turns produce an impression of energy, danger, tension, or interruption. Option C, only smoothness, is wrong because a zigzag is made of angular turns rather than a smooth continuous curve. Option D, round form, is wrong because circles and curved lines more directly suggest roundness. In art, effects can vary with context, but among these choices B is clearly the best. Memory cue: zigzag means sharp energy.