Final answer:
Insulin glargine has the longest duration of action, lasting up to 24 hours, making it the correct answer among the options provided. This type of insulin is used to provide a consistent level of insulin for extended blood glucose management.
Step-by-step explanation:
The type of insulin with the longest duration of action among the options provided is glargine. Insulin glargine is a long-acting basal insulin analogue designed to maintain a consistent level of insulin in the body for an extended period, usually up to 24 hours. Regular insulin, also known as Humulin R, has a shorter duration of action, typically between 3 to 6 hours. NPH, Neutral Protamine Hagedorn, is an intermediate-acting insulin with a duration of action that ranges from 12 to 16 hours, making it longer-acting than regular insulin but not as long as glargine. Therefore, for managing blood glucose levels, insulin glargine is chosen when a prolonged effect is desired, such as for baseline insulin coverage.