A green mixture appears too dark and bluish. What should be done to make it more balanced?

Correct answer: Add a little yellow

The governing concept is adjustment of colour proportion. Green is made from yellow and blue; when the mixture is too blue, adding a small amount of yellow moves the balance toward a more even green. Option B is correct. Red may neutralise green and make it dull or brownish, violet adds more blue bias, and black changes the value by making the mixture darker rather than balanced. Add the correction gradually.