Which mixture is useful for the lit area of a violet flower?

Correct answer: Violet with white

The governing concept is tint and value. Adding white to violet produces a lighter tint, which can represent a petal area receiving more light while retaining the flower’s violet identity. Much black creates a shade suited to a darker region, not the lit area. Green or orange changes the colour relationship and may muddy or neutralise the violet instead of simply increasing its lightness. Therefore, option A is the appropriate mixture for the highlighted part.