Which method is suitable for creating a clean light detail over dark acrylic colour?

Correct answer: Dry the base and apply opaque light colour with a clean small brush

The governing concept is opacity and controlled layering. A dark acrylic base should first dry so the detail does not mix with or disturb it. An opaque light colour, applied with a clean small brush, gives stronger coverage and sharper edges, especially for small marks. Therefore option C is correct. A wet base, excessive water, or rubbing can blur the detail, weaken coverage, or damage the underlying layer.