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
In complete denture construction labio-dental sound F & V are used to determine the: 
Select and explain. 
A. Vertical placement of upper anterior teeth, B. Labia-lingual position of anterior teeth, C. Anterio posterior position of anterior teeth, D. Space between tongue and anterior part of hard palate
A: Vertical placement of upper anterior teeth
Answer: A: Vertical placement of upper anterior teeth 
Explanation: None