This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology and breast, Subject name: Surgery
[{'content': 'A 35 years old lactating mother presnted with a painful breast lump. Out of the following, which is the first investigation to be doner ? \nSelect and explain. \nA. Mammography, B. USG, C. MRI, D. X-ray', 'role': 'user'}, {'content': 'Answer: B \nExplanation: in case of pregnancy and lactation,the preferred method employed for the diagnosis of carcinoma breast includes USG,it is more preferred over mammography due to lesser radiation exposure. ref:SRB&;s manual of surgery,ed 3,pg no 480', 'role': 'assistant'}]