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': 'All of the following are true about blood staining of the cornea except: \nSelect and explain. \nA. Its occurrence is hastened by the raised intraocular pressure, B. It clears from centre towards periphery, C. Its clearance may take 2 years or more, D. Visual prognosis is usually poor in such cases', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. It clears from centre towards periphery', 'role': 'assistant'}]