This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Carbohydrates, Subject name: Biochemistry
[{'content': 'During prolonged fasting, rate of gluconeogenesis is determined by: \nSelect and explain. \nA. Essential fatty acid in liver, B. Alanine in liver, C. Decreased cGMP, D. ADP in liver', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B. Alanine in liver(Ref: Harpers 29/e page 160, Harper 31/e page 172)Major Substrates for GluconeogenesisQGlucogenic Amino Acid LactateGlycerolPropionate (Major contributor in Ruminants)', 'role': 'assistant'}]