According to the PMBOK Guide, 7th edition, one of the key activities of the project manager is to implement risk responses to address the issues and opportunities that may affect the project objectives and outcomes. This includes executing contingency plans, which are predefined actions or strategies that are triggered by the occurrence of a risk event. In this scenario, the missing input from the vendor is a risk event that has extended the critical path of the project, which means that the project schedule is at risk of being delayed. Therefore, the project manager should execute a contingency plan to address the issue with the vendor and recover the lost time. Option D is the best answer for this question.
Option A is not the best answer because starting an audit of the vendor’s processes and procedures is not the next thing that the project manager should do. It is a possible action that the project manager may take to identify the root cause of the miscommunication and prevent it from happening again, but it is not a timely or effective action to resolve the current issue. Moreover, starting an audit may not always be feasible or desirable, as it may increase the project costs and risks, and may damage the relationship with the vendor.
Option B is not the best answer because reviewing lessons learned from previous projects with this vendor is not the next thing that the project manager should do. It is a good practice to learn from past experiences and apply them to current projects, but it is not a relevant or helpful action to deal with the current issue. Reviewing lessons learned may not always be accurate or reliable, as the vendor may have changed their processes or procedures since the previous projects.
Option C is not the best answer because making a detailed analysis on vendor issues during the project is not the next thing that the project manager should do. It is a possible action that the project manager may take to monitor and evaluate the vendor’s performance and identify any gaps or improvements, but it is not a proactive or adaptive action to address the current issue. Making a detailed analysis may not always be necessary or appropriate, as it may delay the project delivery and may not reflect the current or future state of the vendor’s situation. References: PMBOK Guide, 7th edition, pages 9-10, 15-16, 25-26, 35-36, 49-50, 59-60.