What may remain lacking if an artist shows distance only by reducing size without changing value or edge contrast?

Correct answer: Credibility of atmospheric depth

The governing concept is the use of multiple depth cues. Objects often appear farther away not only because they become smaller, but also because their values become less distinct and their edges softer or less sharply contrasted. If only size is reduced, the scene may feel diagrammatic rather than atmospheric. Option B is correct; colour variety, object count, and texture realism are not the most direct missing cues.