Which mixture can create a muted blue without simply adding black?

Correct answer: Add a little orange to blue

The governing concept is muting a hue through a small amount of its complementary colour. Orange is complementary to blue, so a little orange reduces blue’s saturation and creates a softer, muted blue without relying on black. White would make a tint rather than simply mute the hue; yellow or green would shift the colour toward green and may not produce the intended neutralised blue. The quantity must remain small, because too much orange can make the result muddy. Option B is correct.