This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urethra & Penis, Subject name: Surgery
During evaluation of the cause of varicocele in a 36-year-old man, attention is directed to the method of drainage of the left testicular vein, which usually enters which of the following? 
Select and explain. 
A. Left adrenal vein, B. Left renal vein, C. Left inferior mesenteric vein, D. Inferior vena cava (IVC)
B: Left renal vein
Answer: B: Left renal vein 
Explanation: The left testicular vein empties into the left renal vein, and the right testicular vein empties into the IVC. Partial occlusion of the right renal vein is an uncommon cause of varicocele and may signify an associated retroperitoneal malignancy.