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: Surgery
Optimum rate of movement during distraction osteogenesis is 
Select and explain. 
A. 1 mm per day, B. 5 mm per day, C. 1 cm per week, D. 5 cm per week
A: 1 mm per day
Answer: A: 1 mm per day 
Explanation: None