You are answering a USMLE-style medical question. Question: A 36-year-old woman comes to the clinic because of tearing and a foreign body sensation in her eyes bilaterally, which has gradually worsened over the last several weeks. She also notes having occasional palpitations, nervousness, sweating, and heat intolerance. Her past medical history is unremarkable. She reports a 20-pack-year smoking history and is currently a daily smoker. Physical examination shows an anxious, trembling woman. She has eyelid retraction bilaterally, with an inability to fully close her eyes. Her extraocular motility is limited on upgaze. There is no thyromegaly, and no thyroid nodules are noted. Laboratory studies reveal a thyroid-stimulating hormone level of 0.1 μU/mL and total T4 of 42 μg/dL. Thyroid-stimulating immunoglobulin is positive. CT scan of the orbits shows proptosis and marked enlargement of the extraocular muscle with sparing of the tendons. Which of the following would most likely transiently worsen this patient’s eye symptoms? Options: A) External orbital radiation B) Selenium supplementation C) Systemic corticosteroids D) Treatment with radioactive iodine Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.