The issue log is a project document where the project manager records the concerns that might turn into potential issues. It is used to document and monitor the resolution of issues. The operations group's concern, which could not be addressed and might turn into a potential issue, should be recorded in the issue log. This allows for tracking and managing the concern until it is resolved. References:
https://www.projectmanager.com/blog/great-project-documentation
https://www.techrepublic.com/article/6-essential-documents-for-project-management-success/

The graph shows that the project is performing below the baseline for both schedule and cost, which means it is behind schedule and under budget. This indicates that the project is not meeting its planned progress and deliverables, and may have some issues with scope, quality, or resources. The project manager should review the project schedule to identify the root causes of the delays, and take corrective actions to bring the project back on track. The project manager should also monitor the project cost to ensure that it does not exceed the budget, and communicate the status and changes to the stakeholders. References:
* PMBOK Guide, 7th Edition, Chapter 8: Performance Measurement and Reporting1
* The PMI Guide to Business Analysis, Chapter 5: Planning Business Analysis Work2
* Business Analysis for Practitioners: A Practice Guide, Chapter 4: Elicitation and Collaboration3

The project manager should develop an integrated change management plan to control the situation, as this will help to establish a clear and consistent process for managing and approving change requests throughout the project. An integrated change management plan defines the roles and responsibilities of the change control board (CCB), the criteria and procedures for evaluating and approving change requests, the tools and techniques for tracking and reporting change requests, and the impact of change requests on the project baselines and other project documents. By developing an integrated change management plan, the project manager can ensure that the change request process is transparent, efficient, and aligned with the project objectives and stakeholder expectations. Redefining the communications management plan may not be sufficient, as it only addresses the information needs and communication methods of the project stakeholders, but not the change request process itself. Documenting the risk in the project risk register may not be relevant, as the question does not indicate that the change request process poses a risk to the project. Reviewing the scope defined in the project charter may not be helpful, as it only provides a high-level overview of the project scope, but not the details of the change request process. References: PMBOK Guide, 7th edition, pages 123, 124, 125, 126.

When discrepancies arise between documented scope and current deliverables, the first step is to understand why and how they occurred. The project manager should work with the team to review the change history and clarify whether these changes were officially approved. This enables informed conversations with stakeholders and potential corrective action.
According to the PMBOK Guide - Seventh Edition (Measurement and Stakeholder Performance Domains), issue resolution starts with identification and root cause analysis before initiating change or communications actions.
Option A addresses communication frequency but not the root cause.
Option C is premature if a valid change was already made.
Option D may be done later but doesn't resolve the current concern.
References:
PMBOK Guide - Seventh Edition, Scope and Stakeholder Performance Domains PMI Change Control Best Practices

According to the PMBOK Guide, the project manager should document the technical reviews with the new change and obtain formal acceptance from the customer before delivering the project. This is part of the Validate Scope process, which ensures that the project deliverables meet the agreed requirements and specifications. By documenting the technical reviews, the project manager can demonstrate the rationale and benefits of the change, as well as the impact on the project scope, schedule, cost, quality, and risk. By obtaining formal acceptance, the project manager can ensure that the customer is satisfied with the project outcome and avoid any disputes or rework later. References: (Professional in Business Analysis Reference Materials source and documents)
* PMBOK Guide, 6th edition, Chapter 5, Section 5.5, Validate Scope
* PMP Exam Prep, 10th edition, Rita Mulcahy, Page 157, Validate Scope