The project manager should mentor the team member and provide the necessary training because this is the best way to help the team member overcome the difficulty and deliver the expected results. Self-organizing teams are empowered to make decisions and collaborate with each other, so the project manager should act as a facilitator and coach rather than a directive leader. The other options are not the best choices because they do not address the root cause of the problem, which is the lack of knowledge or skills in the new technology.
Requesting the team member to move to another team (option A) may demotivate the team member and create resentment. Delegating other team members to complete this team member's tasks (option B) may overload the other team members and reduce the team cohesion. Including this team member in an improvement program through a human resources request (option D) may imply that the team member is underperforming and needs to be disciplined, which may lower the team member's morale and confidence. References:
PMBOK Guide, 6th edition, pages 18, 52, 273, 335. Free PMP Practice Exam Questions - 120 Sample Test Questions. PMI PMP Quiz:82 Topic:3 Questions:406-410.