This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Anatomy
[{'content': "Regarding stones in gallbladder the following are true except \nSelect and explain. \nA. Mixed stones are common in the west, B. In saint's traid diveiculosis of colon and hiatus hernia coexist, C. 90% of GB stones are radiopaque, D. Is a risk factor for development", 'role': 'user'}, {'content': 'Answer: C \nExplanation: Cholesterol stones are Radiolucent stones Majority of stones pigment and Mixed stones are radiolucent So almost 90% are radiolucent not Radiopaque Ref: Sabiston 20th edition Pgno :1494', 'role': 'assistant'}]