The correct option is C All of the above
The pancreas is one of the most important glands of the digestive system in human. It is located in the abdominal cavity, behind the stomach, which is upper left part of the abdomen. The tissues with an endocrine role can be seen under staining as lightly-stained clusters of cells, called as Pancreatic islets, also called as Islets of Langerhans. Islets of Langerhans contain four different type of cells, that is, alpha cells, beta cells, delta cells, and pp cells also called as F cells. The F cells constitute only 5% of islet cells. It secretes pancreatic polypeptide.