Which mixture is used to make blue-green?

Correct answer: Blue and green

The governing concept is the relationship between adjacent colours and tertiary hues. Blue-green lies between blue and green on the colour wheel, so mixing blue with its neighbouring secondary colour, green, creates blue-green. Thus option B is correct. Yellow-orange, red-violet, and red-orange are valid neighbouring pairs for other tertiary colours, but none produces the blue-green result asked for here.