This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: NEET 2019, Subject name: Surgery
Flask shaped ulcers in colon is caused by:- 
Select and explain. 
A. Giardia lamblia, B. Entamoeba histolytica, C. H. Pylori, D. Enterobius vermicularis
B: Entamoeba histolytica
Answer: B: Entamoeba histolytica 
Explanation: Amoebiasis: M/C pathogenic amoeba in humans - E. histolytica Trophozoites of E. histolytica attaches to submucosa of cecum & ascending Colon to produce "FLASK SHAPED ULCERS" and causes abscess.