All are tests to check eustachian tube patency except -
This question can be solved even if we dont know all tests for eustachian tube patency, because we know fistula test is for assessing vestibular functions and not for Eustachian tube patency. Still it is worth while knowing tests for eustachian tube patency.
Valsalva maneuver
Fistula test
Frenzel's maneuver
Toynbee's maneuver