<prompt> Among the following the least common cause of acute upper GI bleeding is?Mallory Weiss tearUlcerVaricesVascular ectasia  <response>: Source of bleeding Propoion of patients, Ulcers 31-67 Varices 6-39 Mallory Weiss tears 2-8 Gastroduodenal erosions 2-18 Erosive esophagitis 1-13 Neoplasm 2-8 Vascular ectasia 0-6 No source identified 5-15 