Pancreas is a large organs present in abdomen and serves as both endocrine and exocrine organ. The endocrine parts of pancreas are islets of Langerhans that have two primary cell types namely, alpha and beta cells. Alpha cells of islets produce and secrete glucagon hormone while beta cells produce insulin. This makes option A correct and option B incorrect. The exocrine part of pancreas secretes digestive enzymes. This makes option C incorrect as glucagon is hormone which is secreted by endocrine glands. The delta cells of endocrine islets of pancreas secrete somatostatin. This makes option D incorrect. Correct answer is A.