This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Obs), Subject name: Gynaecology & Obstetrics
[{'content': 'A woman presents with amenorrhea of 6 weeks duration and lump in the right iliac fossa. Investigation of choice is: \nSelect and explain. \nA. USG abdomen, B. Laparoscopy, C. CT scan, D. Shielded X-ray', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. is a, i.e. USG abdomenThe answer is quite obvious and I do not think you need any reference for this one.X-ray and CT scan should be avoided during pregnancy due to risk of radiation exposure.', 'role': 'assistant'}]