Final answer:
The Priority technical order improvement recommendation requires a reply within 45 days, to make sure important issues are addressed promptly.
Step-by-step explanation:
The technical order (TO) improvement recommendation that requires a reply within 45 days is the Priority recommendation. When someone identifies an error or possibility for improvement in an Air Force technical order, they can submit a recommendation for change. There are different categories of recommendations such as Routine, Priority, and Critical, each having its own set response time. The Priority TO improvement recommendation is the one that necessitates a response in a specified timeframe, which is 45 days, to ensure that significant but not immediately dangerous issues are handled in a timely manner.