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
Which is the first non-succedaneous tooth to erupt into the oral cavity: 
Select and explain. 
A. Mandibular central incisor., B. Mandibular first molar., C. Maxillary first molar., D. Maxillary central incisor.
B: Mandibular first molar.
Answer: B: Mandibular first molar. 
Explanation: Mandibular central incisor is the first succedaneous tooth to erupt in the oral cavity.
Mandibular 1st molar is the first non-succedaneous tooth to erupt in the oral cavity.