What is the best plan when both value and colour temperature must change in a complex gradation?

Correct answer: Plan value and temperature changes separately in stages

The governing concept is planned colour mixing in a controlled gradation. Value describes the lightness or darkness, while temperature describes the warm or cool tendency; planning both variables in stages prevents accidental jumps and muddy transitions. A small study can establish the sequence before the final work. Random strokes, only black and white, or untested direct mixing cannot control both changes, so option A is correct.