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': 'All of the following materials are radiopaque in nature except: \nSelect and explain. \nA. Zinc phosphate, B. Composite, C. Gutta percha, D. Amalgam', 'role': 'user'}, {'content': "Answer: B \nExplanation: All given options are metallic (radiopaque) in nature except composite resins.\nGenerally, non-metallic radiopaque markers (gutta-percha, composite resin) are used in MDCT imaging and CBCT imaging studies to minimize the effect of image artifacts produced by metal\xa0markers.\n\n\xa0\nReference: White and Pharoah's Oral Radiology Principles and Interpretation 7th edition page no 637", 'role': 'assistant'}]