What can gradual strokes from light to dark colour be called?

Correct answer: Gradation

The governing concept is gradation, in which colour, value, or tone changes progressively rather than abruptly. A stroke that moves from a lighter area toward a darker area demonstrates a gradual tonal transition, so option B is correct. Stamping makes repeated impressions, scraping removes or drags material, and dotting builds an image with separate points rather than a continuous light-to-dark change.