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: Dental
[{'content': 'First sound by child is: \nSelect and explain. \nA. Sibilant, B. Bilabial, C. Fricative, D. Monolabial', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Most children are able to produce the bilabial sounds (made with the lips) of “b, p, m, w” ﬁrst, since\xa0these are sounds visible on the lips.\xa0\nThey may also produce sounds (linguo-alveolar) such as “d, n, t” early on as well.\nThese sounds are called linguo-alveolar, since they are produced with the tongue behind the teeth\xa0against the alveolar ridge in the mouth.', 'role': 'assistant'}]