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
What are the objectives of furcation therapy: 
Select and explain. 
A. Facilitate maintenance., B. Prevent further attachment loss., C. Obliterate the furcation defects as a periodontal maintenance problem., D. All of the above.
D: All of the above.
Answer: D: All of the above. 
Explanation: The objectives of furcation therapy are to

Facilitate maintenance
Prevent further attachment loss and
Obliterate the furcation defects as a periodontal maintenance problem. The selection of therapeutic mode varies with the class of furcation involvement, the extent and configuration of bone loss, and other anatomic factors.