How can a muted violet-grey for a natural shadow be created?

Correct answer: Add a little yellow to violet then adjust value with white or black

The governing concept is complementary neutralisation: yellow lies opposite violet on the colour wheel, so a small amount of yellow reduces violet’s intensity and produces a muted violet-grey. After neutralising the hue, white can raise the value or black can lower it. Option A is correct because it controls chroma first and value second; the other choices do not reliably create a violet-grey shadow.