Which condition results from the body's inability to produce insulin?

Diabetes is a chronic illness that occurs when the body is unable to produce enough insulin or properly utilize the insulin it produces. Insulin is a hormone produced by the pancreas that is essential for regulating blood sugar levels. In diabetes, specifically type 1 diabetes, the body's immune system attacks the insulin-producing beta cells in the pancreas, leading to little to no insulin production. In type 2 diabetes, the body may produce insulin, but the cells become resistant to its effects, resulting in elevated blood sugar levels.

The other conditions listed—asthma, cystic fibrosis, and epilepsy—are unrelated to insulin production. Asthma is primarily a respiratory condition affecting the airways, cystic fibrosis is a genetic disorder that affects the lungs and digestive system, and epilepsy is a neurological condition that causes seizures. None of these conditions involves the regulation of blood sugar or insulin production, making diabetes the only correct answer regarding the body's inability to produce insulin.