Provide your best answer for the following question. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The question is: An apple appears red when struck by white light. This appearance is because the red light is reflected and the other colors are absorbed. What color will this apple appear to be when struck by blue light?
black
Blue or purple. (The exact color depends on the specific apple and the wavelengths of the blue light.)