This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitamins and Minerals, Subject name: Biochemistry
[{'content': 'Why does Vit B6 deficiency lead to anemia? \nSelect and explain. \nA. ALA synthase is affected, B. Iron absorption is affected, C. RBC life span is reduced, D. B6 deficiency leads to bleeding', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ALA synthase catalyses the first and rate limiting step of heme synthesis PLP (Vitamin B6) is necessary for this reaction. That is why B6 deficiency can also lead to anemia', 'role': 'assistant'}]