The correct answer is option 'B' - Insulin and glucagon.

Explanation:
Somatostatin is a hormone that is primarily produced by the delta cells of the pancreas. It functions as a regulatory hormone and is involved in the control of various physiological processes in the body.

The source of somatostatin is the same as that of insulin and glucagon, which are also hormones produced by the pancreas. Let's understand the sources of these hormones in detail:

1. Insulin:
Insulin is a hormone that is produced by the beta cells of the pancreas. It plays a crucial role in regulating blood sugar levels. Insulin helps in the uptake and utilization of glucose by cells, thereby reducing the concentration of glucose in the bloodstream.

2. Glucagon:
Glucagon is another hormone produced by the alpha cells of the pancreas. It functions in opposition to insulin. When blood glucose levels are low, glucagon is released and acts on the liver to stimulate the breakdown of glycogen into glucose. This process is called glycogenolysis and helps in increasing the concentration of glucose in the bloodstream.

3. Somatostatin:
Somatostatin is produced by the delta cells of the pancreas, which are interspersed among the alpha and beta cells. It is involved in the regulation of both insulin and glucagon secretion. Somatostatin inhibits the release of insulin and glucagon, thereby playing a role in maintaining the balance of glucose in the bloodstream.

All three hormones - insulin, glucagon, and somatostatin - are derived from the pancreatic islets of Langerhans, which are clusters of cells in the pancreas responsible for hormone production. While insulin and glucagon have opposing effects on blood sugar levels, somatostatin acts as a regulator of their secretion.

In conclusion, the source of somatostatin is the same as that of insulin and glucagon, all of which are produced by the pancreas.