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': 'In a high copper amalgam, the phase which is eliminated is: \nSelect and explain. \nA. Gamma 1, B. Gamma 2, C. Gamma 1 and 2, D. No phase is eliminated', 'role': 'user'}, {'content': 'Answer: B \nExplanation: A reaction between Cu3 Sn (ε phase) and γ2\xa0occurs and yields Cu6Sn5\xa0 (η\xa0phase). Because of the low copper content, a majority of γ2\xa0remains. The addition of more than 6% of copper by weight can reduce or eliminate the γ2\xa0phase by the formation of\xa0Cu-Sn phase.\nReference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, 12th ed page no 344', 'role': 'assistant'}]