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
Lactose nonfermenting are all except - 
Select and explain. 
A. Shigella sonnei, B. Shigella dysenteriae, C. Shigella flexneri, D. Shigella boydii
A: Shigella sonnei
Answer: A: Shigella sonnei 
Explanation: Ans. is 'a' i.e., Shigella sonnei * Lactose and sucrose are not fermented except by Sh. Sonnei which ferment them late.