What can generally be created by using only two of the three primary colours?

Correct answer: A secondary colour and its variations

The governing concept is the formation of secondary colours. In a basic pigment system, mixing two primary colours creates one secondary colour: red with yellow gives orange, yellow with blue gives green, and blue with red gives violet. Changing the relative amounts produces lighter, darker, or warmer-looking variations of that mixture. Hence option D is correct; the process does not produce only white, no new colour, or necessarily only neutral colours.