Why is it better to prepare separate mixtures instead of repeatedly adding white to one mixture when making dark-to-light values?

Correct answer: Each value remains controlled and reusable

The governing concept is a controlled value scale. Preparing separate mixtures lets the artist compare each lightness level, reproduce it later, and avoid accidentally making the whole mixture too pale or uneven through repeated additions. Option A is correct. White is still used, drying time does not become immediate, and separate mixtures do not remove the need to clean brushes.