This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Radiology
[{'content': 'Nipple shadows in chest xray characteristically have a sharp \nSelect and explain. \nA. Medial margin, B. Lateral margin, C. Superior margin, D. Inferior margin', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Miller et al proposed that solitary pulmonary nodules that reach some or all of the following criteria can be considered nipple shadows :Bilateral and symmetric"fuzzy" margins or radiolucent "halo"Sharp lateral border and poorly defined medial border (may be present only on pa projections 3)Nodules are in a characteristic position:Male: between fifth and sixth rib anteriorlyFemale: at the inferior aspect of the breast shadowWere not present on a very recent filmProminent nipples may be visible on a lateral projectionHowever, if there is doubt repeat chest x-ray with nipple markers should be performed.(Ref: Miller WT, Aronchick JM, Epstein DM et-al. The troublesome nipple shadow. AJR Am J Roentgenol. 1985;145 (3): 521-3.)', 'role': 'assistant'}]