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': "Most common ovarian tumour to undergo torsion is : \nSelect and explain. \nA. Pseudomucinous cystadenoma, B. Brenner's tumour, C. Adenomyoma, D. Dermoid cyst", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Dermoid cyst', 'role': 'assistant'}]