This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ovarian Tumors, Subject name: Gynaecology & Obstetrics
[{'content': 'Which is bilateral tumour:- \nSelect and explain. \nA. Dysgerminoma, B. Immatureteratoma, C. Endodermal sinus tumur, D. Embryonal cell carcinoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In the choices of this question, all tumors are of Germ Cell origin. Germ Cell tumors are Mostly Unilateral eg, The endodermal sinus tumour is unilateral in 100% of cases However, dysgerminoma can have 10-15 % bilaterality & teratoma are bilateral in 15% of patients The Epithelial tumors of the ovary are the most common Ovarian tumors and these are bilateral mostly', 'role': 'assistant'}]