This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bleeding from the GUT and diseases of esophagus, Subject name: Medicine
Among the following the least common cause of acute upper GI bleeding is? 
Select and explain. 
A. Mallory Weiss tear, B. Ulcer, C. Varices, D. Vascular ectasia
D: Vascular ectasia
Answer: D: Vascular ectasia 
Explanation: 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