This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gynaecological Disorders in Obs., Subject name: Gynaecology & Obstetrics
[{'content': 'The following primary tumors are common in the vulva except: \nSelect and explain. \nA. Adenocarcinoma, B. Basal cell carcinoma, C. Choriocarcinoma, D. Squamous cell carcinoma', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is c, i.e. ChoriocarcinomaRef: Dutta Gynae 6th/ed, p334Histological types of vulval cancers* Squamous cell carcinoma-90%* Melanoma 5%* Adenocarcinoma (Bartholin's gland)* Basal cell carcinoma* Sarcoma", 'role': 'assistant'}]