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 caused by? \nSelect and explain. \nA. Flutamide, B. Cimetidine, C. Pyrazinamide, D. Methotrexate', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (b) CimetidineRef Appendix-39 for \'Drugs causinggynaecomastia"', 'role': 'assistant'}]