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': 'Action of Antidote of heparin (Protamine) is based on: \nSelect and explain. \nA. Competitive antagonism, B. Chemical antagonism, C. Non competitive antagonism, D. Toxic reaction', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Chemical antagonism', 'role': 'assistant'}]