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
Distance between undersurface of hygienic pontic and gingiva is 
Select and explain. 
A. 1 mm, B. 1.5 mm, C. 2 mm, D. 2.5 mm
C: 2 mm
Answer: C: 2 mm 
Explanation: None