This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T., Subject name: Radiology
Rat tail appearance is seen in? 
Select and explain. 
A. Esophageal carcinoma, B. Gastric ulcer, C. Achlasia cardia, D. Congenital hypertrophic pyloric stenosis
A: Esophageal carcinoma
Answer: A: Esophageal carcinoma 
Explanation: Ans. is 'a' i.e., Esophageal carcinoma * A barium swallow study showing Rat tail sign i.e. narrowing of barium streak at the level of esophagus is a characteristic feature of esophageal carcinoma.