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 superior border of lingual bar should lie 
Select and explain. 
A. Deep in the lingual sulcus, B. At least 4 mm below the gingival margin, C. At the cingutum of anterior teeth, D. At least 7 mm below the gingival margin
B: At least 4 mm below the gingival margin
Answer: B: At least 4 mm below the gingival margin 
Explanation: None