Final answer:
Insulin is the only option for therapy in type 1 diabetes because the body does not produce enough insulin. Insulin injections are more effective than oral pills for controlling the disease.
Step-by-step explanation:
The nurse should explain to the client that insulin is the only option for therapy because their body does not produce an adequate amount of insulin. Insulin is a hormone that helps cells take up glucose from the blood, and without it, blood glucose levels rise to harmfully high levels. While there are oral pills available for diabetes treatment, they are not as effective as insulin at controlling the disease. Insulin injections allow for precise dosage and immediate effects, while oral pills take longer to produce therapeutic effects.