This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Surgery
[{'content': 'patient having inguinal mass likely diagnosis ? \nSelect and explain. \nA. anal ca., B. prostate ca., C. testiclar ca., D. penile ca.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Lymphatic drainage of anal canal is through the mesorectal (also known as inferior rectal) nodes to the inguinal and femoral nodes. Anal cancers are more likely to produce inguinal adenopathy, with internal iliac adenopathy also occurring when the tissues near the anorectal junction are involved. ref : bailey and love', 'role': 'assistant'}]