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
[{'content': 'When solid gets wet completely, the contact angle is: \nSelect and explain. \nA. 90°, B. 0°, C. 0 — 90°, D. >90°', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]