Explanation
According to the PMBOK Guide, 7th edition, one of the key principles for project delivery is to "enable team members and stakeholders to align their efforts and work as a team" (p. 13). Thisprinciple implies that the project manager should support the team members in developing their skills, knowledge, and capabilities, and provide them with the necessary resources, tools, and guidance. The project manager should have allocated additional time for mentoring the intern, as this would have helped the intern to learn from the senior engineer, gain confidence, and contribute effectively to the project. Requesting an experienced resource, convincing the critical resource, or negotiating additional time are not effective ways to handle the situation, as they do not address the root cause of the problem, which is the lack of adequate training and support for the intern. References: PMBOK Guide, 7th edition, p. 13; PMP Exam Content Outline, Domain II: Process, Task
6.