During an Examination,the Nurse Notices Severe Nystagmus in Both Eyes

During an examination,the nurse notices severe nystagmus in both eyes of a patient.Which conclusion by the nurse is correct? Severe nystagmus in both eyes:

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.