<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 75-year-old man is brought to the emergency room after being found unconscious in his home. His medical history is unknown. On physical examination he does not demonstrate any spontaneous movement of his extremities and is unable to respond to voice or painful stimuli. You notice that he is able blink and move his eyes in the vertical plane. Based on these physical exam findings, you expect that magnetic resonance angiogram will most likely reveal an occlusion in which of the following vessels?? A: Anterior cerebral artery, B: Anterior spinal artery, C: Anterior inferior cerebellar artery, D: Basilar artery, E: Posterior cerebral artery,  <response>: This is a clinical vignette describing a 75-year-old man found unconscious at home. The key findings on physical exam are no spontaneous movement of extremities, no response to voice or pain, but preserved vertical eye movements. This indicates a lesion in the ventral pons affecting the corticospinal and corticobulbar tracts that control limb movement and consciousness, but sparing the pathways controlling vertical eye movements. The question asks which vessel is most likely occluded based on these findings. The basilar artery supplies the ventral pons. Occlusion of this vessel could cause the described deficits. The other answer choices describe vessels supplying other brain regions not consistent with the exam findings.D: Basilar artery 