If a colour consistently appears darker after drying what should be done for accurate mixing?

Correct answer: Keep the wet mixture slightly lighter based on a dry sample

The governing concept is accounting for a predictable drying shift. If the medium repeatedly dries darker, the wet mixture should be prepared slightly lighter and judged against a dried test sample. This creates a practical correction rather than relying on the misleading wet appearance. Thus A is correct. Adding black worsens the darkening, stopping tests removes useful evidence, and changing paper alone does not correct a consistent pigment or medium shift.