This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology (Gram Positive Bacilli, Gram Negative Bacilli), Subject name: Microbiology
[{'content': 'In the laboratory, the screening procedure used to differentiate Salmonella and Shigella from other Enterobacteriaceae includes testing for their inability to: \nSelect and explain. \nA. Ferment glucose, B. Ferment lactose, C. Produce cytochrome oxidase, D. Reduce nitrates', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Inability to ferment lactose is used to differentiate Salmonella and Shigella from other Enterobacteriaceae. Option 1, 3, 4 Enterobacteriaceae propeies: Ferments glucose Reduces nitrate to nitrite Oxidase test negative Catalase positive (except Shigella dysenteriae type-1) Motile, except Shigella and Klebsiella. Option 2 Lactose fermenters Non Lactose fermenters Escherichia Klebsiella Enterobacter Other members of Enterobacteriaceae family including Salmonella and Shigella.', 'role': 'assistant'}]