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 measurements in four types of hand-mixed  cements  showed  that __________  cement had the highest porosity. 
Select and explain. 
A. Resin cement, B. GIC, C. Zinc phosphate cement, D. Polycarboxylate cement
D: Polycarboxylate cement
Answer: D: Polycarboxylate cement 
Explanation: Porosity measurements in four types of hand-mixed cements showed that polycarboxylate cement had the highest porosity and resin cement had the least. Zinc phosphate and GICs had intermediate amounts of porosity.
Ref: Phillip’s Science of Dental Materials ed 12 pg 320