When measuring a patient's visual acuity, the nurse is assessing which cranial nerve?

A. I: Cranial nerve I, the olfactory nerve, is responsible for the sense of smell and is not involved in visual acuity; it can be tested by asking the patient to identify familiar scents. B. II: Cranial nerve II, the optic nerve, is responsible for transmitting visual information from the retina to the brain. It is directly involved in measuring visual acuity, as it enables the nurse to assess how well the patient can see and interpret visual stimuli; visual acuity is commonly tested using the Snellen chart. C. IV: Cranial nerve IV, the trochlear nerve, controls the superior oblique muscle, which is responsible for downward and lateral eye movement. It can be assessed by having the patient follow an object in a downward diagonal direction. D. III: Cranial nerve III, the oculomotor nerve, controls most of the eye's movements, including constriction of the pupil and maintaining an open eyelid. It is assessed by evaluating the patient's ability to follow objects in all directions and checking for pupil response to light and accommodation.