What is the best method to achieve even coverage while filling a flat area with poster colour?

Correct answer: Keep an even consistency and move the brush in one direction

The governing concept is uniform flat application. The paint should have a consistent thickness, and regular strokes in one direction should overlap slightly without repeatedly disturbing the wet layer. Option A is correct because it produces an even film with predictable coverage. Varying water, scrubbing wet paint with a dry brush, or changing colour on every stroke creates streaks and patchy results.