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': 'Discoloration of a denture constructed from cold cure acrylic resin is due to: \nSelect and explain. \nA. Absorption of oral fluids, B. PH changes in saliva, C. Leaching out of tertiary amines, D. Leaching out of excess monomer', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]