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: Surgery
[{'content': 'Reactionary hemorrhage is hemorrhage after surgery that occurs \nSelect and explain. \nA. Within 24 hours, B. After 24 hour, C. After 72 hours, D. After 7 days', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]