During Examination, the Nurse Notices Severe Back and Forth Oscillations

During examination, the nurse notices severe back and forth oscillations in both eyes of the patient.Which conclusion by the nurse is correct regarding the findings? This:

A) Is a normal occurrence
B) May indicate disease of the cerebellum or brainstem
C) Is a sign that the patient is nervous about the examination
D) Indicates a visual problem, and a referral to an ophthalmologist is indicated