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: Pharmacology
[{'content': 'Adrenaline is added to lignocaine to prolong its effect and decrease its absorption into blood stream in a ratio of : \nSelect and explain. \nA. 1:50,000, B. 1:100,000, C. 1:200,000, D. 1:500,000', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]