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: Anatomy
[{'content': 'Which of the following prominence is unpaired: \nSelect and explain. \nA. Frontonasal, B. Maxillary, C. Mandibular, D. None of the above', 'role': 'user'}, {'content': "Answer: A \nExplanation: The frontonasal prominence is a single unpaired structure; the other prominences are paired. Ref: Langman's embryology 11th edition Chapter 16.", 'role': 'assistant'}]