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
[{'content': 'Best indicator for sterilization by autoclaving ? \nSelect and explain. \nA. Bacillus subtilis, B. Geobacillus, C. Bacillus pumilis, D. Clostridium', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Geobacillus Biological indicators Biological indicators are standardised preparations of microorganisms used to assess the effectiveness of a sterilization process. They usually consist of a population of bacterial spores placed on an ine carrier, for example a strip of filter paper, a glass slide or a plastic tube. Most commonly, spores of Bacillus stereothermophilus (Geobacillus stearothermophilus) are used. Spores of Bacillus subtilis and Bacillus pumilis are alse used.", 'role': 'assistant'}]