A 42-year-old woman from Delhi presents to the endocrinology clinic for evaluation of hypertension (BP 164/102 mmHg) and episodic palpitations with diaphoresis. Plasma metanephrines are markedly elevated. On examination, she has a firm, non-tender thyroid nodule. TSH is normal, but fine-needle aspiration cytology (FNAC) shows C-cell hyperplasia and focal medullary thyroid carcinoma (MTC). Serum calcium is 10.8 mg/dL and PTH is 78 pg/mL (normal 15–65). Her 16-year-old daughter has been found to have elevated calcitonin (45 pg/mL; normal <10) on routine screening. What is the most likely diagnosis?