This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General, Subject name: Microbiology
[{'content': 'Bacillus used to test efficacy of Sterilisation by Autoclave is? \nSelect and explain. \nA. Bacillus subtilis., B. Bacillus pumilis., C. Bacillus stearothermophilus, D. Coxiella burnetti.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: ANSWER: (C) Bacillus stearothermophilusREF: Basic medical laboratory techniques 4th edition by Barbara H. Estridge, Anna P. Reynolds,Norma J. Walters Page 70Various bacilli are used to check efficacy of sterilisation methods are:Autoclave- Bacillus stearothermophilusHot air oven- Bacillus subtilis subspecies nigerIonising radiation- Bacillus pumilis', 'role': 'assistant'}]