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: Microbiology
An example of high level disinfectant is 
Select and explain. 
A. Phenol, B. Glutaraldehyde, C. Alcohol, D. Povidone Iodine
B: Glutaraldehyde
Answer: B: Glutaraldehyde 
Explanation: None