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 of the following present similar to unruptured ectopic pregnancy \nSelect and explain. \nA. Follicular cyst of ovary, B. Corpus luteum cyst, C. Polycystic ovary disease, D. Ovarian torsion', 'role': 'user'}, {'content': "Answer: B \nExplanation: Halban's classical traid:\n\nDelay in normal period followed by spotting\nUnilateral pelvic pain\xa0\nSmall Tender adnexal mass.\n\nThis triad is similar to that seen in classic ectopic pregnancy.", 'role': 'assistant'}]