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 TCA cycle of tricarboxylic acid, which is first formed 
Select and explain. 
A. Isocitrate, B. Citrate, C. Succinate, D. Fumarate
B: Citrate
Answer: B: Citrate 
Explanation: B i.e. Citrate