This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Colon and Rectum - Benign Colonic Disorders, Subject name: Surgery
[{'content': "Investigation of choice to diagnosis Hirschsprug's disease is: \nSelect and explain. \nA. Rectal manometry, B. Barium enema, C. Rectal biopsy, D. Laparotomy", 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e. Rectal biopsy RepeatYou already know about the features of Hirschsprung's disease seen on contrast enema from the question asked earlierMore about the diagnosis of Hirschsprung's disease -Definitive diagnosis of Hirschsprung's disease is made by Rectal biopsy :It demonstrates following features-Absence of ganglion cells in Meissner's plexus, and myenteric plexusHypertrophy of nerve trunksManometric study - Manometric studies will show a failure of relaxation of internal sphincter following rectal distension.", 'role': 'assistant'}]