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 is not helpful in diagnosis of tubal mass in ectopic pregnancy \nSelect and explain. \nA. Beta-HCG estimation, B. Hysterosalpingography, C. Transvaginal ultrasound, D. Pelvic examination', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. b. Hysterosalpingography', 'role': 'assistant'}]