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: Radiology
[{'content': 'Sensitivity of mammography is low in young females because \nSelect and explain. \nA. Young breast have dense tissue, B. Young breast have more fat, C. has less fat, D. less glandular tissue', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Young females have dense brest tissue,thus sensitivity of mammo is low.', 'role': 'assistant'}]