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: Pediatrics
[{'content': 'Most common cause of severe hematemesis in a child is- \nSelect and explain. \nA. Poal hypetension, B. Peptic ulcer, C. Mallory weiss syndrome, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. is \'a\' i.e., Poal hypeension "Massive hematemesis in a child is almost always due to variceal bleeding". Variceal bleeding is due to poal hypeension.', 'role': 'assistant'}]