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 of these conclusions by the nurse is correct?

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