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: Unknown
[{'content': 'Filament in X-ray made of: \nSelect and explain. \nA. Tungsten filament, B. Chromium, C. Gallium, D. Selenium', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Please remember: Target is not Tungsten inmammography, its made up off molybdenum.', 'role': 'assistant'}]