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
Green shrinkage seen in 
Select and explain. 
A. Phosphate bonded investment., B. Ethyl silicate bonded investment., C. Gypsum bonded investment., D. All of the above.
B: Ethyl silicate bonded investment.
Answer: B: Ethyl silicate bonded investment. 
Explanation: • Green shrinkage:
-Occurs during heating of silicate investments.
-Occurs due to loss of alcohol & water during phase(168ºC) to form a concentrated, hard gel.
This also leads to volumetric contraction of the mould