You are answering a USMLE-style medical question. Question: A 40-year-old woman presents to her family physician with a 3-week history of swollen neck. The small, round, and painless swelling, which was detected 3 weeks ago in the middle of her neck, has now increased in size. The swelling is associated with sweaty palms and soles, insomnia, irritability, nervousness, and fatigue; however, the patient does not complain of fever, cervical lymphadenopathy, weight loss, vision problems, or body swelling. The patient’s medical history is negative for similar symptoms or a thyroid disorder. The vital signs are within normal limits. Local examination reveals a 3 x 3 cm round, non-tender, non-fluctuant, and non-pulsatile swelling in the anterior triangle of her neck. The patient carries a total white blood cell count of 10,200/mm3, including 70% neutrophils, 30% lymphocytes, and zero eosinophils.The erythrocyte sedimentation rate is 20 mm/hr (normal, 0–29 mm/hr). What is the most likely diagnosis? Options: A) Graves' disease B) De Quervain’s thyroiditis C) Silent thyroiditis D) Hashimoto’s thyroiditis Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.