Linear coefficient of thermal expansion of composites is: (A) 1 ppm/ oC, (B) 40 ppm/ oC, (C) 260 ppm/ oC, (D) 1000 ppm/ oC
Answer is B. 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