A warm-to-cool transition is smooth but the middle colour appears disconnected from both ends. What is the correction?

Correct answer: Include controlled proportions of both end colours in the middle colour

The governing concept is a continuous colour bridge. A convincing transition requires the intermediate mixture to contain controlled portions of both the warm and cool endpoint colours, with the proportions changing gradually across the passage. Option D is correct because it creates visual and chromatic connection. Adding only black dulls the mixture, separating the ends increases discontinuity, and opacity does not solve the relationship problem.