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': 'Porosity of denture base is due to: \nSelect and explain. \nA. Packing at dough stage, B. Curing at 160°F for 9 hrs, C. Inadequate pressure, D. All of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]