On what basis should brush size be selected for colour filling?

Correct answer: According to the size and detail of the area to be filled

Brush selection is governed by the size of the area, the amount of coverage required and the level of detail. A broad brush covers a large background efficiently, while a smaller brush gives control near edges and in fine shapes. Price, the painter’s name and the paper title do not determine suitability. Therefore option A gives the practical basis for selection.