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
Bell's palsy not responding to the steroid. What will be the further line of management - 
Select and explain. 
A. Increase the dose of steroid, B. Vasodilators and ACTH, C. Surgical decompression, D. Electrophysiological nerve testing
D: Electrophysiological nerve testing
Answer: D: Electrophysiological nerve testing 
Explanation: If the patient of Bell's palsy is not responding to conservative treatment, electrodiagnostic study (electrophysiological study) should be done.
The electrodiagnostic study includes electromyography (EMG), Electroneurography (ENG), minimal excitability test and maximal excitability test.
Surgery is reserved for those who meet electrodiagnostic (electrophysiological) study criteria or are worsening on medical treatment.