According to the PMBOK Guide, 7th edition, one of the key activities of the project manager is to tailor the project delivery approach based on the project characteristics, context, and environment. This means that the project manager should select the appropriate tools, techniques, methods, and artifacts that best suit the project needs and objectives. If the project manager realizes that the project will benefit from using adaptive tools, such as agile or hybrid methods, then the project manager should update the project documents accordingly and plan the first iterative session. This will enable the project team to deliver value incrementally and iteratively, and to respond to changes and feedback more effectively. Option A is the best answer for this question.

Option B is not the best answer because contacting the project sponsor and requesting new team members who are familiar with adaptive projects is not the first thing that the project manager should do. It is a possible action that the project manager may take if the current team lacks the skills or experience to work with adaptive tools, but it is not a necessary or immediate action. Moreover, requesting new team members may not always be feasible or desirable, as it may increase the project costs and risks, and may disrupt the team dynamics and performance.

Option C is not the best answer because confirming team capabilities before introducing adaptive tools and artifacts to the project is not the first thing that the project manager should do. It is a good practice to assess the team’s readiness and ability to work with adaptive tools, but it is not a prerequisite or a determinant for tailoring the project delivery approach. The project manager should base the decision on the project characteristics, context, and environment, not on the team capabilities. Moreover, confirming team capabilities may not always be accurate or reliable, as the team may have different levels of familiarity and confidence with adaptive tools.

Option D is not the best answer because freezing the design stage and looking for an external resource to run iterative design at extra cost is not the first thing that the project manager should do. It is a possible action that the project manager may take if the project is too complex or uncertain to be handled by the internal team, but it is not a recommended or proactive action. Freezing the design stage may delay the project delivery and may not reflect the current or future state of the project requirements or stakeholder needs. Looking for an external resource may increase the project costs and risks, and may reduce the project control and quality. References: PMBOK Guide, 7th edition, pages 9-10, 15-16, 25-26, 35-36, 49-50.