This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Rectum, Subject name: Surgery
Regarding to the anorectal angle, True Statement is: 
Select and explain. 
A. Important role in continence mechanism, B. It is due to the pull of the external sphincter, C. It is around 30 degrees at rest, D. The angle decreases at the time of defection
A: Important role in continence mechanism
Answer: A: Important role in continence mechanism 
Explanation: Ans. (a) Important role in continence mechanismRef: Internet sources* Most important ring to maintain the continence is this angle* During rest the angle is completely closed with an angle of 90deg-100deg* The angle becomes more acute 70deg-90deg if patient contracts anal sphincter and pelvic floor muscles - so that stools are prevented from coming out.* During Squatting the angle becomes obtuse (> 110- 180 degree and opens up and the motion passed.