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': 'Thalidomide, used for multiple myeloma, is : \nSelect and explain. \nA. Associated with diarrhea, B. Characterized by enantiomeric interconversions, C. Metabolized extensively by hepatic CYP system, D. Safe for use in pregnant females', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]