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: Dental
Gutta-percha is radio-opaque due to presence of: 
Select and explain. 
A. Zinc oxide eugenol, B. Barium sulphate, C. Potassium sulphate, D. Barium oxide
B: Barium sulphate
Answer: B: Barium sulphate 
Explanation: None