This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
[{'content': 'Classical example of transplacental carcinogenesis is - \nSelect and explain. \nA. Teratoma, B. Primary squamous cell carcinoma of vagina, C. Sarcoma botryoids, D. Clear cells adenocarcinoma of vagina', 'role': 'user'}, {'content': 'Answer: D \nExplanation: A series of genotypic and phenotypic changes in the fetus due to utero exposure to carcinogens.. Extensive metastasis. Clear cells adenocarcinoma of vagina.. A rare type. Of cancer. Often linked to diethylselbisterol drug administration.', 'role': 'assistant'}]