Final answer:
The most challenging stage of de jure standardization process is Enforcement. Enforcement requires vigilant monitoring and regulation to maintain compliance with established standards. Agenda setting is the stage in public policy where problems are identified and prioritized.
Step-by-step explanation:
The last and most difficult stage of the de jure standardization process is typically considered to be d. Enforcement. After a standard has been established and implemented, ensuring that all relevant parties remain in compliance can be challenging. Enforcement involves monitoring, regulation, and sometimes legal action to ensure that the standards are followed properly.
Regarding the other question provided for reference, the stage of the public policy process which includes the identification of problems in need of fixing is a. agenda setting. It is during this stage where issues are identified, discussed, and prioritized by policymakers before they become the focus of policy development and subsequent enactment.