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
Porosity of denture base is due to: 
Select and explain. 
A. Packing at dough stage, B. Curing at 160°F for 9 hrs, C. Inadequate pressure, D. All of the above
C: Inadequate pressure
Answer: C: Inadequate pressure 
Explanation: None