1.A 27-year-old man has been diagnosed with primary mediastinal non-seminomatous germ cell tumors (NSGCTs). His serum alpha fetoprotein (AFP) is 12,500 ng/mL, beta-hCG is 33,000 mIU/mL, and lactate dehydrogenase (LDH) is 2,700 U/L. He is anticipated to undergo postchemotherapy resection of residual mediastinal disease and is at risk of perioperative bleomycin-related lung toxicity. The oncologist elected to treat him with VIP. He received chemotherapy from days 1 to 5: etoposide 75 mg/m² IV + ifosfamide 1,200 mg/m² IV + cisplatin 20 mg/m² + Mesna (2-mercaptoethane sulfonate sodium [natrium, Na]) 240 mg/m² IV bolus on day 1 followed by 1,200 mg/m² continuous IV infusion on days 1 to 5. The cycle will be repeated every 3 weeks for four cycles. On day 7, he develops suprapubic pain and hematuria. Which of the following compounds is most likely responsible for this patient’s symptoms?

A. Ifosfamide

B. Mesna

C. Cisplatin

D. Etoposide

E. Metastatic germ cell tumor to the bladder