This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fundamentals in Radiology, Subject name: Radiology
[{'content': 'X-ray Aifact is - \nSelect and explain. \nA. A radiolucent area, B. Any abnormal opacity in the radiograph, C. Produced when patient moves while taking the shoot, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Common aifacts (all forms of radiography) motion aifact due to patient movement resulting in a distoed image image compositing (or twin/double exposure) superimposition of two structures from different locations due to double exposure of same film/plate radiopaque objects on/external to the patient (e.g. debris in the housing debris in the housing caused by the collimator tube can cause small trapezoidal regions, indicative of lead shavings', 'role': 'assistant'}]