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
A 10-year-old child with primary molars in various stages of exfoliation has a slight crowding in the lower anterior. The clinician should: 
Select and explain. 
A. Observe him after 1 year, B. Obtain study casts and perform arch-length	analysis, C. Observe him after 6 months, D. Delay the treatment until all permanent teeth erupt
B: Obtain study casts and perform arch-length	analysis
Answer: B: Obtain study casts and perform arch-length	analysis 
Explanation: None