This answer is based on the best practice of issue management in project management, which is to identify, analyze, prioritize, and resolve issues that affect the project performance, scope, schedule, quality, or budget12. The first step in this process is to rate the severity of the impact the issue has on the project, which involves assessing the likelihood and consequences of the issue, and assigning a rating or score to the issue based on a predefined scale or criteria34. By rating the severity of the impact, the project manager can determine the urgency and importance of the issue, and decide the appropriate course of action to address the issue56. Rating the severity of the impact is better than the other options because:
Buying a replacement for the faulty equipment may not be feasible, cost-effective, or timely, depending on the availability, price, and delivery time of the equipment. It may also require approval from the project sponsor or other stakeholders, and may affect the project budget or scope7.
Getting the maintenance team to resolve the issue may not be possible, depending on the nature and extent of the malfunction, the skills and availability of the maintenance team, and the warranty or service contract of the equipment. It may also take time and resources to diagnose and fix the problem, and may cause further delays or disruptions to the project8.
Escalating the issue to the project sponsor may not be necessary, depending on the severity and complexity of the issue, and the authority and responsibility of the project manager. It may also create unnecessary alarm or confusion among the project stakeholders, and may undermine the project manager's credibility or autonomy9.
References = CompTIA Project+ Certification Study Guide, CompTIA Project+ Certification Exam Objectives, What is Issue Management?1, Issue Management Process2, How to Assess the Severity of Project Issues3, How to Prioritize Project Issues4, How to Replace Faulty Equipment in Project Management5, How to Manage Equipment Maintenance in Project Management6, How to Escalate Issues in Project Management7

An issue log is used to document and track problems that arise during a project, including unforeseen events like the departure of a project manager. It helps in recording the issue, assigning responsibility, and tracking the resolution process. This tool is essential for maintaining project continuity and ensuring that issues are addressed promptly.
Per the CompTIA Project+ PK0-005 exam objectives, under Domain 2.5: Given a scenario, perform issue management activities, maintaining an issue log is a key activity for tracking and managing project issues effectively.

The project manager is creating a quality assurance plan when identifying multiple techniques that will help
the project team ensure confidence and alignment with the project scope and goals during a brainstorming
meeting. A quality assurance plan is a plan that defines and documents the standards, criteria, methods,
activities, and tools for ensuring and verifying that the quality requirements and expectations of a project are
met. A quality assurance plan can help to improve the quality of the project processes and deliverables and
prevent or reduce defects or errors.

A transition plan is a document that outlines how the project deliverables will be transferred to the operations team or the end users, and how the project team will disengage from the project. It typically includes details such as operational training, go-live date, support arrangements, roles and responsibilities, and acceptance criteria. A transition plan is different from a project closeout report, which summarizes the project performance, lessons learned, and final status. A handover to operations is a process of transferring the project deliverables to the operations team, but it is not a document. A phase-gate review documentation is a set of documents that are used to evaluate the project progress and readiness to move to the next phase, but it is not related to the operational handoff. Reference = CompTIA Project+ PK0-005 Certification Study Guide, Chapter 14: Closing the Project, p. 409-410; [CompTIA Project+ Certification Exam Objectives], Domain 4: Project Closure, Objective 4.1: Compare and contrast various project closure activities.