This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Glaucoma, Subject name: Ophthalmology
[{'content': "Sickle-shaped extension of blind spot is known as \nSelect and explain. \nA. Down's sign, B. Bjerrum's sign, C. Seidel's sign, D. Baring of blind spot", 'role': 'user'}, {'content': "Answer: C \nExplanation: Seidel's scotoma: With the passage of time paracentral scotoma joins the blind spot to form a sickle shaped scotoma known as Seidel's scotoma. Ref:-A K KHURANA; pg num:-219", 'role': 'assistant'}]