This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Misc. (R.B.C), Subject name: Pathology
[{'content': 'RBC contains? \nSelect and explain. \nA. Iron, B. Folic acid, C. Vitamin C, D. Biotin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) IronRef: Robbings pathology 9th ed. /631, 649', 'role': 'assistant'}]