The correct option is D Pylorus
The pylorus is a narrow cone-shaped constriction present at the end of the stomach and the beginning of the small intestine. It contains two region antrum which connects the parts of the stomach and pyloric canal which connects the stomach and small intestine. The main functions of the pylorus are to prevent intestinal contents from reentering the stomach when the small intestine contracts to limit the passage of large food particles or undigested material into the intestine. Thus, the correct answer is option D.