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': 'After mixed dentition stage, the arch length from first molar to first molar usually: \nSelect and explain. \nA. Remains same, B. Increases, C. Decreases, D. Double', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Decrease in arch length : The arch decreases in the mixed and permanent dentition stages as a result of the uprighting of the incisors and the loss of the leeway space by the mesial movement of the first permanent molars.\nText book of orthodontics Gowrishankar 1st Ed P:92', 'role': 'assistant'}]