You are answering a USMLE-style medical question. Question: A 27-year-old man presents to the emergency department. He was brought in by staff from the homeless shelter when they found him unresponsive. The patient is a known IV drug abuser but otherwise has an unknown past medical history. He currently attends a methadone clinic. His temperature is 99.5°F (37.5°C), blood pressure is 97/48 mmHg, pulse is 140/min, respirations are 29/min, and oxygen saturation is 98% on room air. Initial laboratory values are shown below. Serum: Na+: 139 mEq/L Cl-: 100 mEq/L K+: 6.3 mEq/L HCO3-: 17 mEq/L Glucose: 589 mg/dL The patient is given treatment. After treatment, his temperature is 99.5°F (37.5°C), blood pressure is 117/78 mmHg, pulse is 100/min, respirations are 23/min, and oxygen saturation is 98% on room air. His laboratory values are seen below. Serum: Na+: 139 mEq/L Cl-: 100 mEq/L K+: 4.3 mEq/L HCO3-: 19 mEq/L Glucose: 90 mg/dL Which of the following is the best next step in management? Options: A) Insulin, potassium, IV fluids, and glucose B) IV fluids only C) Oral rehydration D) Supportive therapy and close monitoring Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.