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
Linear coefficient of thermal expansion of composites is 
Select and explain. 
A. 1 ppm/ oC, B. 40 ppm/ oC, C. 260 ppm/ oC, D. 1000 ppm/ oC
B: 40 ppm/ oC
Answer: B: 40 ppm/ oC 
Explanation: Linear coefficient of thermal expansion:

TOOTH : 9-11 PPM/ oC 
AMALGAM : 25 
GOLD : 15  
COMPOSITES : 40 
GIC : 25 
DENTAL WAXES : HIGHEST 260-600 PPM/ oC 

Reference- Sturdevant 6th ed P:237