A project risk relates to potential issues that could affect the overall success of the project. Among the options provided, the risk that "Team members' skills may not be sufficient for the assigned work" is clearly a project risk because it pertains to the potential failure of the project due to inadequate skillsets among the team. This risk affects the entire project's ability to meet its objectives.References:
* ISTQB Certified Tester Foundation Level Syllabus v4.0, Section 1.4.2.