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
As compared to permanent tooth, root formation in primary tooth: 
Select and explain. 
A. Take less time, B. Take more time, C. Same time, D. Is complete when tooth erupts in oral cavity
A: Take less time
Answer: A: Take less time 
Explanation: None