Which movement is suitable for creating a broad petal centre and a thin tip in one stroke?

Correct answer: Start lightly, press in the middle, and lift at the end

The governing principle is pressure variation during a single brush stroke. Beginning lightly makes a narrow entry, pressing in the middle spreads the bristles to create the broad petal centre, and lifting gradually narrows the ending. Thus option D is correct. Constant light pressure, tip-only drawing, or a stationary press cannot produce this broad-to-thin form.