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': 'Festooned pupil results from: \nSelect and explain. \nA. Irregular dilatation of pupil with atropine in the presence of segmental posterior synechiae, B. Annular synechiae, C. Occlusion pupillae, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Irregular dilatation of pupil with atropine in the presence of segmental posterior synechiae', 'role': 'assistant'}]