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: Gynaecology & Obstetrics
Which of the following is the most common site of secondaries in a case of choriocarcinoma? 
Select and explain. 
A. Vagina, B. Urethra, C. Lung, D. Brain
C: Lung
Answer: C: Lung 
Explanation: In 75% of cases metastasis from choriocarcinoma occurs into the lungs and rest usually occurs in the vagina. Other organs which may also contain metastases are vulva, kidneys, liver, ovaries, brain and bowel.