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
Which of the following is an example of physiological antagonism ? 
Select and explain. 
A. Heparin–Protamine, B. Prostacycline–Thromboxane, C. Adrenaline–Phenoxybenzamine, D. Physostigmine–Acetylcholine
B: Prostacycline–Thromboxane
Answer: B: Prostacycline–Thromboxane 
Explanation: None