The correct option is (a) Auditory Evoked Potential
Best explanation: One of the methods to measure changes in the levels of consciousness during anesthesia is Auditory Evoked Potential (AEP) which is a neuro-physiological indicator of the changes in the level of consciousness during anesthesia. In this, the person is given an auditory stimulus and the EEG response of the person is noted. This allows the doctor to realize the level of consciousness of the person.