A 19-year-old college student has had a sore throat, mild abdominal pain, and fever for 5 days. He was playing football with some friends, and was tackled just short of the goal line, hitting the grass somewhat forcibly. He experiences some abdominal pain, and passes out. The EMS (emergency medical services) is called and his vital signs reveal the heart rate as 140 beats per minute and blood pressure as 80/40 mm Hg with a distended abdomen. Which of the following is the most likely etiology? A. Vasovagal reaction B. Ruptured aortic aneurysm C. Complications of Epstein-Barr infection D. Ruptured jejunum