Review Question - QID 108923

A 25-year-old male rugby player presents to the emergency room complaining of a severe headache. He is accompanied by his teammate who reports that he had a head-to-head collision with another player and briefly passed out before regaining consciousness. His past medical history is significant for a pilocytic astrocytoma as a child treated successfully with surgery. His family history is notable for stroke in his father. His temperature is 98.9°F (37.2°C), blood pressure is 160/90 mmHg, pulse is 60/min, and respirations are 20/min. On examination, he is lethargic but oriented to person, place, and time. The affected vessel in this patient directly branches from which of the following vessels?