Why is it useful to preserve the lightest areas first when planning filling and blending?

Correct answer: Lost light areas may be difficult to recover later

The governing concept is value planning: artists usually build darker tones gradually while protecting highlights. Once a light paper area is covered with dark pigment, restoring its original brightness may be difficult, especially in media that do not lift cleanly. Preserving the lightest shapes first therefore keeps the full range of values available. Dark paint does dry, and light colours do not damage brushes. Thus option C is correct.