This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: ENT
At what angle is the hallpike thermal caloric test done? 
Select and explain. 
A. 15deg, B. 30deg, C. 45deg, D. 60deg
B: 30deg
Answer: B: 30deg 
Explanation: In the Hallpike test, the head is tilted 30deg forward so that horizontal canal is veical. (Ref: Diseases of EAR, NOSE, THROAT by PL DHINGRA; 6th Edition; Page no. 43)