This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Which of the following would be least likely to cause an ulcer in distal esophagus? 
Select and explain. 
A. HSV, B. Achalasia cardia, C. Severe reflux esophagilis, D. Zenkers diverticulum
D: Zenkers diverticulum
Answer: D: Zenkers diverticulum 
Explanation: Zenkers diverticulum occurs at the junction of thyro and cricopharyngeus i.e above the esophagus it doesn't cause ulcer in distal esophagus.