This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Adverse Drug Effect, Subject name: Pharmacology
[{'content': 'Gynaecomastia is side effect of all, EXCEPT : \nSelect and explain. \nA. Ranitidine, B. Cimetidine, C. Spironolactone, D. Ketoconazole', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e. Ranitidine You must have noticed till now the number of repetitions this topic has, so learn the drugs causing gynecomastia well.", 'role': 'assistant'}]