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': 'Diethylstilbestrol should never be used in pregnant women because it is associated with: \nSelect and explain. \nA. Development of deep vein thrombosis in the pregnant woman, B. Feminization of the external genitalia of male offspring, C. Infertility and development of vaginal cancer in female offspring, D. Virilization of the external genitalia of female offspring', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]