This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
[{'content': 'Choriocarcinoma is differentiated from invasive mole (chorioadenoma destruens) by: \nSelect and explain. \nA. Presence of high titre of urinary chorionic gonadotrophin, B. Presence of cannon ball shadow in the lungs, C. Absence of villi structure on histological examine of the lesion, D. All of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Choriocarcinoma can be considered a carcinoma of chorionic epithelium. The characteristic difference from hydatidiform mole is the absence of villous pattern.(refer pgno:172 sheila textbook of obstetrics 2 nd edition)', 'role': 'assistant'}]