正解:C
If a project manager continues to receive project-related work after the project has been released into production, it suggests that the project closure phase was not completed properly. The project closure phase involves several activities, including ensuring that all project deliverables are accepted, documenting the lessons learned, releasing project resources, and formally closing the project. If these activities are not completed, the project can remain 'open' in a sense, leading to continued work and inquiries.
References = The answer is based on standard project management practices and the importance of the project closure phase as described in project management literature. For detailed information, please refer to the CompTIA Project+ Study Guide and other official CompTIA resources. Specific references to the closure phase can be found in the CompTIA Project+ PK0-005 Cert Guide1 and the CompTIA Project+ Certification Exam Objectives2.