What generally results from mixing all three secondary colours in roughly equal amounts?

Correct answer: Neutral brown or grey

In subtractive paint or pigment mixing, the three secondary colours are orange, green, and violet. Together they contain the primary colour components red, yellow, and blue. Mixing them in approximately equal amounts absorbs light across much of the spectrum, so the result normally becomes a dull neutral brown or grey rather than a bright colour. Thus option B is correct; white belongs to additive light mixing, while pure yellow and blue ignore the full mixture.