Which combination is most effective for creating tree-bark texture with a dry brush in acrylic painting?

Correct answer: Little paint and a rough surface

Dry-brush technique works when the brush carries only a small amount of relatively thick paint. On a rough surface, the bristles touch raised areas and leave broken, irregular marks, which resemble tree bark. Option A combines both necessary conditions. A wet brush or excess water would make a smooth wash, while oil is not required for this acrylic technique.