A 78-year-old man with metastatic prostate cancer presents to the emergency department 2 days after initiating chemotherapy with complaints of severe muscle weakness, diffuse cramping, and paresthesias. His wife reports he has had minimal urine output since yesterday. Vital signs: BP 142/88 mmHg, HR 92 bpm, RR 18, Temp 37.2°C, SpO2 98% on room air. Laboratory studies show: Serum calcium: 6.2 mg/dL (normal albumin 4.1 g/dL) Phosphate: 5.8 mg/dL Potassium: 6.8 mEq/L Creatinine: 2.4 mg/dL (baseline 0.9) Uric acid: 12.5 mg/dL PTH: 380 pg/mL (normal 15-65) Alkaline phosphatase: normal Electrocardiography shows peaked T waves. Which of the following best explains this clinical presentation?

1. A)Tumor lysis syndrome with secondary hyperphosphatemia and hypocalcemiaGABARITO
2. B)Primary hyperparathyroidism exacerbated by chemotherapy-induced renal dysfunction
3. C)Vitamin D deficiency from decreased sun exposure during cancer treatment
4. D)Osteoblastic metastases with increased bone turnover and calcium sequestration
5. E)Hypoalbuminemia from hepatic metastases causing decreased serum calcium binding