This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Orbit, Subject name: Ophthalmology
[{'content': "What is the cause for enlargement of muscle shown in this CT-scan? \nSelect and explain. \nA. Pseudotumor, B. Myositis, C. Rhabdomyosarcoma, D. Grave's ophthalmopathy", 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. (d) Grave's ophthalmopathyRef: Parson's, 22/e, p. 487Thyroid eye disease produce typical Fusiform enlargement of extraocular muscles and spares the tendon.", 'role': 'assistant'}]