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': 'Which of the following is an example of physiological antagonism ? \nSelect and explain. \nA. Heparin–Protamine, B. Prostacycline–Thromboxane, C. Adrenaline–Phenoxybenzamine, D. Physostigmine–Acetylcholine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]