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': 'Dysfunctional uterine bleeding is defined as abnormal bleeding due to : \nSelect and explain. \nA. Thyroid dysfunction, B. Functioning ovarian tumour, C. Anovulatory cycle, D. Blood dyscrasias', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Anovulatory cycle', 'role': 'assistant'}]