A46-year-old former salesman presents to the er complaining of black stools for the past few weeks. his past medical history is significant for cirrhosis. he has gained weight recently, especially around his abdomen. he has smoked two packs of cigarettes a day for 30 years and has drunk approximately 10 alcoholic beverages a day for 25 years. he has used iv heroin and smoked crack in the past. he denies any recent use. he is currently unemployed and has never been married. examination shows a man appearing older than his stated age. his skin has a yellowish tint and he is thin with a prominent abdomen. multiple "spider angiomas" are at the base of his neck. otherwise his heart and lung examinations are normal. on inspection he has dilated veins around his umbilicus. increased bowel sounds are heard during auscultation. palpation reveals diffuse tenderness that is more severe in the epigastric area. his liver is small and hard to palpation and he has a positive fluid wave. he is positive for occult blood on his rectal examination.
what cause of black stools most likely describes his symptoms and signs?
a) infectious diarrhea
b) mallory-weiss tear
c) esophageal varices