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
Eruption of Deciduous Mandibular 1st molar occur at 
Select and explain. 
A. 8-9 months, B. 19-21 months, C. 19-20 months, D. 12-14 months
D: 12-14 months
Answer: D: 12-14 months 
Explanation: None