This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdomen and pelvis, Subject name: Anatomy
[{'content': 'The left testicular vein drains into which of the following veins? \nSelect and explain. \nA. Left internal iliac vein, B. Left common iliac vein, C. Inferior vena cava, D. Left renal vein', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The left testicular vein drains into the left renal vein. The right testicular vein drains directly into the inferior vena cava. This difference in venous drainage is believed to explain the greater incidence of varicocele on the left side than on the right. The venous drainage from the penis is to the internal vein, which then drains into the internal iliac vein.', 'role': 'assistant'}]