What is the most complete basis for evaluating the quality of colour filling and blending?

Correct answer: Even coverage clean edges controlled tones and smooth transitions

The governing concept is holistic technical evaluation. High-quality colour filling should cover the area evenly, keep edges intentional and clean, maintain controlled light-to-dark tones, and create smooth transitions where blending is required. Brightness alone ignores accuracy and control; brush size is only a tool variable, and price is unrelated to execution. Therefore option C includes the complete set of relevant criteria.