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
Filters used to purify air in biological safety cabinets? 
Select and explain. 
A. HEPA (High efficiency particulate air), B. Sietz filters, C. Berkfield filters, D. Millipore/Porcelain filters
A: HEPA (High efficiency particulate air)
Answer: A: HEPA (High efficiency particulate air) 
Explanation: None