This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of carbohydrate, Subject name: Biochemistry
Pair of organs involved in cahill cycle? 
Select and explain. 
A. Liver and muscle, B. liver and kidney, C. liver and brain, D. muscle and kidney
A: Liver and muscle
Answer: A: Liver and muscle 
Explanation: None