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: Social & Preventive Medicine
[{'content': 'Toxin causing endemic ascites \nSelect and explain. \nA. BOAA, B. Pyrrolizidine alkaloids, C. Aflatoxin, D. Sanguinarine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]