The correct answer is C. Identify the risk of implementing the new solution and evaluate the impact on the project.
Before starting a project, it is essential to identify potential risks and evaluate their impact on the project. In this scenario, enhancing an existing product means introducing changes to an already established system, which increases the risk of failure or delays. Therefore, the project manager should identify the risks associated with the new solution and evaluate their potential impact on the project's success. This will allow the project team to develop a risk management plan to mitigate or avoid potential issues.
While stakeholder engagement, lessons learned, and documentation are also important, identifying risks is critical in the initiation phase to ensure the project's success. Therefore, options A, B, and D are not the best initial actions for the project manager to take