This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Development of GU system and Neuro-vascular supply of pelvis & perineum, Subject name: Anatomy
An elderly man with prostatic hyperophy returns to his urologist with another case of epididymitis. An acute infection involving the daos muscle layer of the scrotum most likely leads to an enlargement of which of the following lymph nodes? 
Select and explain. 
A. Preaoic nodes, B. Lumbar nodes, C. External iliac nodes, D. Superficial inguinal nodes
D: Superficial inguinal nodes
Answer: D: Superficial inguinal nodes 
Explanation: The superficial inguinal lymph nodes receive lymph from the scrotum, penis, buttocks, and lower pa of the anal canal, and their efferent vessels enter primarily to the external iliac nodes and ultimately to the lumbar (aoic) nodes. The deep inguinal nodes receive lymph from the testis and upper pas of the vagina and anal canal, and their efferent vessels enter the external iliac nodes.