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: ENT
Not  a Tests for Eustachian Tube 
Select and explain. 
A. Glycerol Test, B. Valsalva Maneuver, C. Frenzel test, D. Tonybee's test
A: Glycerol Test
Answer: A: Glycerol Test 
Explanation: None