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: Pathology
[{'content': 'One of the following is due to point mutation- \nSelect and explain. \nA. Colour blindness, B. Sickle cell anemia, C. Diabetes, D. Pophyria', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Sickle cell anemia", 'role': 'assistant'}]