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: Medicine
The toxicity of etambutol includes one of the following: 
Select and explain. 
A. Peripheral neuritis, B. Green colour blindness, C. Red urine, D. Yellow colour blindness
B: Green colour blindness
Answer: B: Green colour blindness 
Explanation: The optic neuritis is the most serious side effect of ethambutol manifesting as reduced visual acuity, central scotoma, and loss of ability to see green colour. Ref: Harrisons Principles of Medicine, 18th edition, page : 1375