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: Pathology
Most common fixative used in electron microscopy: 
Select and explain. 
A. Glutaraldehyde, B. Formalin, C. Picric acid, D. Absolute alcohol
A: Glutaraldehyde
Answer: A: Glutaraldehyde 
Explanation: Ans. a. Glutaraldehyde