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': 'The cause of decreased outflow of aqueous in a case of primary open angle glaucoma in diabetic: \nSelect and explain. \nA. Block in episcleral veins, B. Lens lymphatic blockage, C. Block in trabecular meshwork, D. Infection of iris', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Block in trabecular meshwork', 'role': 'assistant'}]