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
Fall in alkalinity of Ca(OH)2 wheh used as a root canal dressing starts at 
Select and explain. 
A. 1 week, B. 2 week, C. 4 week, D. 12 week
A: 1 week
Answer: A: 1 week 
Explanation: None