If a green watercolour is too blue and too dark what correction order is appropriate?

Correct answer: First correct hue with yellow then lighten value with water

The governing concept is controlled correction of hue and value as separate properties. Since the green is too blue, a small amount of yellow first shifts the hue toward a balanced green. Since it is also too dark, water can then lighten the value while retaining watercolour transparency. Thus option B is correct. Adding black worsens darkness, mixing everything removes control, and red or white does not provide the most direct correction for the stated errors.