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
[{'content': 'Which of the following is not seen on hemoglobin electrophoresis in sickle cell anemia - \nSelect and explain. \nA. HbA, B. HbA2, C. HbF, D. HbS', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]