This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
[{'content': 'A 20 year old male presents with scrotal mass. The first investigation to be done is \nSelect and explain. \nA. Clinical evaluation (Palpation and transillumination), B. USG, C. Biopsy, D. AFP', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Differential diagnosis are hydrocele, hematocele, epididymal cyst, spermatocele, varicocele, inguinal hernia, testicular tumours . Thus clinical examination should be done first to differentiate between them.', 'role': 'assistant'}]