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
After scaling of a patient, scaler tip is Cleaned by: 
Select and explain. 
A. Under running H2O for 2 minutes, B. Hot air oven, C. Dipping in phenol disinfectant for 24 hour, D. Chemical vapors
C: Dipping in phenol disinfectant for 24 hour
Answer: C: Dipping in phenol disinfectant for 24 hour 
Explanation: None