Dry-brush technique is most useful for showing the texture of which subject?

Correct answer: Rough wood

Dry-brush marks are broken because the brush carries little moisture and does not form a completely even film. Such irregular strokes are useful for representing a visibly rough, grainy surface, such as wood. Option A is therefore correct. Smooth glass needs controlled, continuous reflections; soft clouds need blended edges; and a clear sky is generally represented with an even wash or smooth gradation, not broken texture marks.