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
Highest pH of the given Root end conditioning material is of: 
Select and explain. 
A. Citric acid., B. Doxycycline., C. EDTA., D. None.
C: EDTA.
Answer: C: EDTA. 
Explanation: citric acid pH=1.
Doxycycline pH= 1.8
EDTA pH= 7.3