This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General Microbiology Pa 1 (History, Microscopy, Stains and Structure and Physiology of Bacteria), Subject name: Microbiology
[{'content': "Kovac's reagent is used in _____ \nSelect and explain. \nA. Methyl red test, B. Voges-Proskauer test, C. Indole test, D. Urease test", 'role': 'user'}, {'content': "Answer: C \nExplanation: Kovac's reagent is used in Indole test Indole test is used to determine the ability of an organism to split amino acid tryptophan to form the compound indole. Indole production is detected by Kovac's or Ehrlich's reagent which contains 4 (p)-dimethylamino benzaldehyde, this reacts with indole to produce a red colored compound. negative indole test positive indole test", 'role': 'assistant'}]