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: Biochemistry
In Krebs cycle, which of the following catalyses the step in which the first CO2 is released? 
Select and explain. 
A. Aconitase, B. Isocitrate dehydrogenase, C. Succinate thiokinase, D. Succinate dehydrogenase
B: Isocitrate dehydrogenase
Answer: B: Isocitrate dehydrogenase 
Explanation: None