What should be corrected if colours in a two-colour brush stroke mix excessively and become muddy?

Correct answer: Rotate the brush less and keep colours on separate edges

In double loading, colour separation must be preserved while the brush travels across the surface. Excessive rotation or twisting causes the two pigments to blend prematurely, producing a dull, muddy mark. Option B is correct because less rotation and separate placement on the brush edges maintain clean colour areas. More water, rubbing, or adding black would usually weaken or dirty the effect rather than correct it.