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: Medicine
The organism which is involved in anaerobic infections of head and neck region is 
Select and explain. 
A. Staphylococcus aureus, B. S. albus, C. Streptococci, D. Bacteroids
D: Bacteroids
Answer: D: Bacteroids 
Explanation: None