A 29-year-old woman presents 3 months postpartum with palpitations, anxiety, and tremor (HR 108/min, BP 138/82, RR 18, T 37.2°C). Several weeks later, she develops fatigue and cold intolerance despite normal appetite. Examination reveals a small, nondtender thyroid without nodules. TSH is 0.2 mIU/L with elevated free T4. Radioactive iodine uptake is low. She denies recent iodine supplementation or medication use. Which diagnosis best explains her clinical presentation?

1. A)Postpartum thyroiditisGABARITO
2. B)Medullary thyroid carcinoma
3. C)Toxic adenoma
4. D)Graves disease
5. E)Subacute granulomatous thyroiditis