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: Gynaecology & Obstetrics
[{'content': 'Which causes torsion of ovarian tumor : \nSelect and explain. \nA. Trauma, B. Uterine contraction, C. Physical movements, D. All', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Trauma', 'role': 'assistant'}]