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
According to the treatment plan plaque control, root planning under: 
Select and explain. 
A. Preliminary phase., B. Etiotropic phase., C. Surgical phase., D. Restorative phase.
B: Etiotropic phase.
Answer: B: Etiotropic phase. 
Explanation: Phase 1 is also known as Etiotropic phase which includes plaque control, diet control, scaling, root planning and temporary restorations.