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
Sterilization of culture media containing serum is by : 
Select and explain. 
A. Autoclaving, B. Micropore filter, C. Gamma radiation, D. Centrifugation
B: Micropore filter
Answer: B: Micropore filter 
Explanation: Most of the culture media are sterilized by Autoclaving at 121°C for 15 min at 15 lb pressure / inch2
Constituents like serum, trypsin, growth factors, proteins, amino acids, vitamins, hormones, carbohydrates and plant extracts are thermolabile and may decompose during autoclaving. Therefore, these must be sterilised by filtration.