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 teratogen causes deafness ? \nSelect and explain. \nA. Isotretnoin, B. Chloroquine, C. Alcohol, D. Warfarin', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Isotretnoid o Isotretinoin can cause microtia or anotia. o These defects are frequently associated with agenesis or stenosis of external ear canal and may lead to deafness.", 'role': 'assistant'}]