How is insulin typically administered?

Insulin is typically administered through subcutaneous and intravenous routes. The subcutaneous injection is the most common method for individuals managing diabetes, as it allows for a controlled release of insulin into the bloodstream from the fatty tissue just beneath the skin. This is essential because insulin needs to be absorbed gradually over time to effectively lower blood sugar levels without causing rapid fluctuations.

Intravenous administration is also used, particularly in hospital settings for individuals requiring immediate or precise control of their blood glucose levels, such as in cases of diabetic ketoacidosis or during surgeries. This method allows for the fastest response as insulin enters directly into the bloodstream.

The other routes, such as oral, intramuscular, or topical, are not standard for insulin administration. Insulin cannot be taken orally because it would be broken down in the digestive system before it can enter the bloodstream. Therefore, C accurately describes the established methods for administering insulin to manage diabetes effectively.