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
Investment material used for cobalt-chromium alloys is: 
Select and explain. 
A. Gypsum bonded, B. Phosphate bonded, C. Silica bonded, D. None of the above
B: Phosphate bonded
Answer: B: Phosphate bonded 
Explanation: None