What is the technique of applying wet watercolour on dry paper called?

Correct answer: Wet-on-dry

Technique names are determined by the state of the paper and the paint. Wet watercolour applied to dry paper is called wet-on-dry, making option D correct. The dry surface limits spreading and helps the artist create relatively clean, controlled edges. Wet-on-wet requires damp paper, dry-brush uses little paint on a nearly dry brush, and glazing means building transparent layers rather than naming this exact condition.