This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pharmacology, Subject name: Pharmacology
Which of the following are physiological antagonists 
Select and explain. 
A. Adrenaline and Isoprenaline, B. glucagon and insulin, C. Isoprenaline and Propranolol, D. All of the above
B: glucagon and insulin
Answer: B: glucagon and insulin 
Explanation: Adrenalin and histamine and glucagon, insulin are physiological antagonists Physiological antagonism - opp effect on the same physiological system by two drugs glucagon increases blood glucose, insulin decreases- blood glucose adrenaline- bronchodilatation histamine- broncho constriction Ref KD Tripathi 8th ed.