A 12-year-old boy is brought to the physician because of a 2-month history of headaches

A 12-year-old boy is brought to the physician because of a 2-month history of headaches and a 6-day history of
nausea and vomiting. Funduscopic examination shows bilateral papilledema. He walks with a broad-based gait. An
MRI of the brain shows a tumor in the pineal region compressing the brain stem and leading to hydrocephalus. This
patient most likely has impairment of which of the following oculomotor functions?
(A) Abduction
(B) Horizontal pursuit
© Optokinetic nystagmus
(D) Upward gaze
(E) Vestibulo-ocular reflex