You are answering a USMLE-style medical question. Question: A 75-year-old woman is brought by a patrolman to the emergency department because of altered mental status. She was found wandering next to the highway. The patient was unable to answer questions and collapsed in transit. Her vitals are: temperature, 33.0°C (91.4°F); pulse, 40/min; respirations,12/min; blood pressure, 80/50 mm Hg; and oxygen saturation, 85% on room air. Physical examination shows decorticate posturing, incomprehensible speech, eyes opening to pain, dry hair, coarse and waxy skin, and non-pitting edema around the face and all extremities. Electrocardiogram shows sinus bradycardia. Laboratory studies show: Calcium 9.0 mg/dL Hematocrit (female) 34% Potassium 4.0 mEq/L Sodium 120 mEq/L TSH 110.0 µU/mL Thyroxine (T4) 1.2 µg/dL Triiodothyronine (T3) 70 ng/dL Which of the following is the most likely diagnosis in this patient? Options: A) Myxedema coma B) Pheochromocytoma crisis C) Septic shock D) Tertiary hyperparathyroidism Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.