<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 25-year-old man presents to his primary care provider complaining of scrotal swelling. He is a college student and plays basketball with his friends regularly. Two days ago, he sustained an injury close to his thigh. He does not have any significant past medical history. Today, his vitals are normal. A focused scrotal examination reveals a firm painless lump on the right testicle which is irregular and small. Ultrasound of the scrotum reveals a vascular 0.6 x 0.5 cm testicular mass. A pelvic lymph node exam is negative. He undergoes a radical orchiectomy and subsequent histopathological examination reveals sheets of small cuboidal cells, multinucleated cells, and large eosinophilic cells with pleomorphic nuclei consistent with choriocarcinoma. Which of the following tumor marker is most likely elevated in this patient?? A: Carcinoembryonic antigen, B: Beta-human chorionic gonadotropin, C: Prostate-specific antigen, D: Placental alkaline phosphatase, E: Testosterone,  <response>: Based on the information provided in the question stem, this is a case of a 25-year-old man with a testicular mass that was diagnosed as choriocarcinoma on histopathology after orchiectomy. The key findings are a testicular mass in a young man, orchiectomy showing choriocarcinoma, and no evidence of metastases based on normal pelvic lymph nodes. Choriocarcinoma is a rare malignant germ cell tumor that can arise from the testes. It secretes high levels of beta-human chorionic gonadotropin beta-hCG, which is used as a tumor marker to monitor response to treatment and detect recurrence. Carcinoembryonic antigen CEA is elevated in some epithelial cancers like colon, not germ cell tumors. Prostate-specific antigen PSA is associated with prostate cancer. Placental alkaline phosphatase can be elevated in seminomas but not choriocarcinomas. Testosterone is not a tumor marker.Therefore, the tumor marker most likely to be elevated in this patient with testicular choriocarcinoma is beta-hCG.B: Beta-human chorionic gonadotropin 