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
Treatment objective for serial extraction: 
Select and explain. 
A. To intercept a developing arch-length deficiency and to reduce or eliminate the need for extensive appliance therapy, B. Reduce arch-length deficiency, C. To plan for extensive appliance therapy, D. To reduce arch-length deficiency & to plan for extensive appliance therapy
A: To intercept a developing arch-length deficiency and to reduce or eliminate the need for extensive appliance therapy
Answer: A: To intercept a developing arch-length deficiency and to reduce or eliminate the need for extensive appliance therapy 
Explanation: Benefits of Serial Extraction 

Serial extraction guides or encourages eruption of permanent teeth in a favorable position.
Reduces malposition of individual teeth.
Avoids loss of labial alveolar bone.
Reduces treatment time when active orthodontic treatment is required. 

Textbook of ORTHODONTICS Sridhar Premkumar