The correct answer is option 2, Islets of Langerhans. The Islets of Langerhans are small clusters of cells located within the pancreas. These cells play a crucial role in controlling blood sugar levels by producing and releasing two important hormones: insulin and glucagon.

Insulin is responsible for reducing blood sugar levels. When the blood sugar levels are high, the beta cells in the Islets of Langerhans release insulin into the bloodstream. Insulin helps glucose (sugar) enter the cells, where it can be used for energy or stored for later use. This process helps to regulate blood sugar levels and prevent them from becoming too high.

On the other hand, glucagon is another hormone produced by the alpha cells in the Islets of Langerhans. Glucagon plays a role in increasing blood sugar levels. When blood sugar levels drop too low, glucagon is released, stimulating the liver to break down stored glycogen into glucose and release it into the bloodstream.

The Pituitary gland (option 1) is involved in the regulation of several hormones, but not specifically in controlling blood sugar levels. The Hypothalamus (option 3) also plays a role in hormone regulation but does not specifically control blood sugar