This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
[{'content': "Earliest field defect in primary open angle glaucoma – \nSelect and explain. \nA. Riedel's scotoma, B. Scotoma in Bjerrums field, C. Arcuate scotoma, D. Nasal spur", 'role': 'user'}, {'content': "Answer: B \nExplanation: Paracentral scotoma appears either below or above the blind spot in Bjerrum's area.", 'role': 'assistant'}]