This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'All of the following helps in maturation of rbc except \nSelect and explain. \nA. Castles intrinsic factor, B. Iron, C. Vit b12, D. Folic acid', 'role': 'user'}, {'content': "Answer: A \nExplanation: Castle's intrinsic factor hepls in b12 absorption", 'role': 'assistant'}]