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
What is the approximate stress caused by polymerisation shrinkage of composite? 
Select and explain. 
A. 1 Mpa, B. 5 Mpa, C. 15 Mpa, D. 30 Mpa
B: 5 Mpa
Answer: B: 5 Mpa 
Explanation: None