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
Vestibular function is tested by -a) Galvanic stimulation testb) Acoustic reflexc) Fistula testd) Impedance audiometrye) Cold caloric test 
Select and explain. 
A. acd, B. bde, C. cde, D. ace
D: ace
Answer: D: ace 
Explanation: Clinical tests

Fistula testQ
Romberg test
Gait
Past-pointing and fallingQ
Hallpike maneuver (positional test)

Lab test

Caloric test

–– Modified (Kobrak’s test)
–– Fitzgerald-Hallpike test (Bithermal caloric test)
–– Cold-air caloric test by Dundas-Grant method. Done in case of perforation of tympanic membrane.

Electronystagmography
Optokinetic test
Rotation test
Galvanic testQ
Posturography