Which is the most precise definition of a tertiary colour?

Correct answer: A mixture of a primary colour and its neighbouring secondary colour

In the standard colour-wheel model, a tertiary colour is produced by mixing a primary colour with the neighbouring secondary colour beside it, such as red with orange to make red-orange. Option A is correct because it states both the component types and their adjacent relationship. Two primary colours normally produce a secondary colour, complementary mixtures tend toward neutral or dull results, and black with white produces a neutral grey.