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
All of the following materials are radiopaque in nature except: 
Select and explain. 
A. Zinc phosphate, B. Composite, C. Gutta percha, D. Amalgam
B: Composite
Answer: B: Composite 
Explanation: All given options are metallic (radiopaque) in nature except composite resins.
Generally, 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 markers.

 
Reference: White and Pharoah's Oral Radiology Principles and Interpretation 7th edition page no 637