This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
[{'content': 'Factors affecting sickling in sickle cell anemia are - \nSelect and explain. \nA. HbS concentration, B. HbA, C. pH, D. Oxygenation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Formation of sickle cell depends on HbS concentration since HbS polymerises and grow beyond the RBC membrane ,prject through it. Referance: Exam preparatory manual for UGs -Pathology by Ramdas Nayak Page no:274 Robbins 9/e pg', 'role': 'assistant'}]