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: Microbiology
[{'content': 'Ascaris lumbricoides causes deficiency of: \nSelect and explain. \nA. Iron, B. Vitamin B 12, C. Folic acid, D. Vitamin A', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Vitamin A', 'role': 'assistant'}]