Which mixture can be used to create a dark colour like maroon?

Correct answer: Add a tiny amount of blue or black to red

The governing concept is shading: a base colour can be darkened by adding a very small quantity of a dark or modifying colour. Red mixed carefully with a little blue or black becomes a deep red that can resemble maroon. White would make red pinker and lighter, while the blue-yellow and green-white mixtures do not produce a maroon-like red. The dark colour must be added gradually to avoid overpowering the red.