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': 'Contamination of zinc-containing amalgam by moisture\nduring trituration or condensation: \nSelect and explain. \nA. Causes a marked expansion, B. Increases the setting time, C. Results in a sharp decrease in flow, D. Has no appreciable effect on amalgam', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]