Which stroke is useful for creating tree-bark texture with acrylic colour?

Correct answer: Broken and rough strokes

The governing concept is visual texture: marks should imitate the visible qualities of the object. Tree bark is usually uneven, cracked, and rough, so broken strokes with varied pressure and direction suggest its irregular surface; therefore option B is correct. A smooth single line suggests a polished surface, a white wash does not by itself describe bark, and very wet spreading tends to flatten or blur the texture. Observe the surface before choosing a stroke.