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': 'Slice of tissue X-rays is - \nSelect and explain. \nA. Tomography, B. Mammography, C. Contrast studies, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In CT, X-rays are used to create axial slices (sections) of the body -\n\n\xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0Slices with exposure to radiation\xa0→ CT\n\xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0Slices without exposure to radiation\xa0→ MRI', 'role': 'assistant'}]