What difference occurs when a brush is moved at a slight angle instead of being held very vertically?

Correct answer: More of the brush can touch the surface and the stroke may become wider

The governing concept is the relationship between brush angle and contact area. A nearly vertical brush usually uses a smaller part of its tip, whereas a slightly tilted brush lets more bristles touch the surface. This can spread paint over a wider path and alter the stroke texture, so option D is correct. The other choices describe effects unrelated to brush angle.