Which of the Following Statements Accurately Describes the Act of Defecation

Which of the following statements accurately describes the act of defecation?

A) Defecation refers to the emptying of the small intestine.
B) Centers in the medulla and the spinal cord govern the reflex to defecate.
C) When sympathetic stimulation occurs, the internal anal sphincter relaxes and the colon contracts sending fecal content to the rectum.
D) Rectal distention leads to a decrease in intrarectal pressure, causing the muscles to stretch and thereby stimulating the defecation reflex.