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: ENT
[{'content': 'Treacher collins syndrome, all are present except - \nSelect and explain. \nA. Aural artesia, B. Webbed neck, C. Hypoplasia of mandible, D. Atrophic lid margins', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]