The servant leader's role is to serve the team, and in this case, the best way to serve is to facilitate communication between the team member and the product owner. This will help the team member understand the requirement directly from the source and clarify any doubts or confusion. The other options may not address the root cause of the problem, which is the lack of understanding of the requirement. References:
Project Management Body of Knowledge (PMBOK) Guide, 6th Edition, Section 3.4: Role of the Project Manager