This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
[{'content': 'All of the following are examples of primary colours, EXCEPT: \nSelect and explain. \nA. Red, B. Green, C. Blue, D. None of the above', 'role': 'user'}, {'content': "Answer: D \nExplanation: The sensation of white, any spectral color, and even the extraspectral color, purple, can be produced by mixing various propoions of red light (wavelength 723-647 nm), green light (575-492 nm), and blue light (492-450 nm). which are therefore called the primary colors. Ref: Ganong's Review of Medical Physiology 23rd edition, Chapter 12.", 'role': 'assistant'}]