What is the technique of creating shading with dots called?

Correct answer: Stippling

The governing concept is mark-making for tonal shading. Stippling builds light and dark values with separate dots; increasing the number or density of dots makes an area appear darker, so option A is correct. Hatching uses repeated lines, smudging blends marks by rubbing, and contour describes an outline rather than a dot-based shading method. Thus the technique is clearly stippling.