<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 6-month-old male presents with a painless, enlarged left scrotum. After examining the patient, you suspect this enlargement is secondary to serous fluid entering and accumulating in the scrotum through a patent processus vaginalis. Which of the following would be the most useful next step in confirming the diagnosis of this patients condition?? A: Measurement of AFP and hCG levels, B: Transillumination test followed by scrotal ultrasound, C: Evaluation of cremasteric reflex on physical exam, D: Measurement of serum testosterone levels, E: Standard urinalysis,  <response>: This is a clinical vignette describing a 6-month-old male infant with an enlarged, painless left scrotum. The stem suggests a working diagnosis of a patent processus vaginalis allowing fluid to accumulate in the scrotum. To confirm this diagnosis, the most useful next step would be a test that can directly visualize the anatomy and determine if there is fluid present. Measurement of tumor markers AFP and hCG would not be useful, as there is no suspicion of a tumor. The cremasteric reflex and serum testosterone would not provide any information about the scrotal contents or anatomy. A urinalysis is not specific for this condition. The best choice would be a transillumination test, which can detect fluid collections, followed by scrotal ultrasound to clearly visualize the anatomy.B: Transillumination test followed by scrotal ultrasound 