Why can three primary colours have different visual weight in a painting even when used in equal physical amounts?

Correct answer: Their value, saturation, area, and context may differ

Visual weight is governed by value, saturation, hue temperature, area, contrast, and surrounding context rather than by physical quantity alone. A bright, highly saturated yellow or red may attract attention differently from a dark blue of the same measured area. Thus equal amounts do not guarantee equal emphasis; the other options incorrectly deny colour and context.