A project charter is a project planning document that sells the project to stakeholders and sponsors. It provides a preliminary delineation of roles and responsibilities, outlines the project's key goals, identifies the main stakeholders, and defines the authority of the project manager. A project charter is essential for any project, regardless of its size or complexity, as it serves the following purposes:
It authorizes the project and grants the project manager the permission to use organizational resources It serves as a primary sales document that summarizes the project's value proposition and return on investment It acts as a roadmap that guides the project team and stakeholders throughout the project lifecycle It helps to manage the project scope and avoid scope creep by establishing the project boundaries and deliverables It facilitates communication and alignment among the project team, sponsors, and stakeholders by clarifying the project objectives, assumptions, risks, and constraints Therefore, the project manager should explain to the sponsor that a project charter is necessary to ensure agreement on scope and deliverables and to define the project manager's responsibilities. Without a project charter, the project may face the following risks:
Lack of clarity and direction for the project team and stakeholders
Misalignment of expectations and goals among the project team, sponsors, and stakeholders Scope creep and change requests that may impact the project schedule, budget, and quality Conflicts and disputes over roles, responsibilities, and authority Reduced stakeholder engagement and support References:
What is a Project Charter? Complete Guide & Examples
How to Write a Project Charter: Examples & Template Included
Project charter - Wikipedia

One of the ways to ensure success in a project is by motivating team members. As the project progresses, stress levels increase, and overall, things turn hostile. All this reduces the motivation of the team1. One of the crucial reasons behind project success is high project team motivation. Organizations with higher-than- average levels of employee engagement see 27% higher profits, 50% higher sales, 50% higher customer loyalty levels, and 38% above-average productivity1. Therefore, initiating rewards and incentives according to assessment results can be an effective way to encourage the team and boost their performance. References:
https://thedigitalprojectmanager.com/projects/leadership-team-management/project-team-motivation/

The project manager should schedule a one-on-one meeting with the team member to talk about the issue and get their cooperation. This is an example of the problem-solving technique, which involves confronting the issue directly and cooperatively to find a mutually acceptable solution1. This technique is usually the most effective way to manage conflict in a project team2. Scheduling a meeting with the team member and their manager to discuss the issue (A) is not a good option since it may create a sense of distrust and resentment in the team member. Talking to the project sponsor about the team member's attitude (B) is also not advisable since it may escalate the conflict and damage the relationship between the project manager and the team member. Finding another person to replace this team member (D) is not a viable option since it would disrupt the project schedule, budget, and scope. References:
* 1: A Guide to the Project Management Body of Knowledge (PMBOK Guide) - Seventh Edition, Chapter 9, Section 9.5.2.2
* 2: A Guide to the Project Management Body of Knowledge (PMBOK Guide) - Seventh Edition, Chapter 9, Section 9.5.2.3