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': 'Mercuroscopic expansion in dental amalgam occurs when: \nSelect and explain. \nA. Moisture contamination occurs during condensation of zinc containing amalgam, B. Moisture contamination occurs during trituration of zinc containing amalgam, C. Mercury released as a result of electrochemical corrosion re-reacts with Ag-Sn particle, D. Mercury released as a result of electrochemical corrosion re-reacts with Ag-Cu particle', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]