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
The tooth brushing method least likely to remove plaque in the gingival margin is the: 
Select and explain. 
A. Sulcular method, B. Scrub method, C. Modified stillman, D. Roll stroke
D: Roll stroke
Answer: D: Roll stroke 
Explanation: None