The project manager should have assessed the organizational culture at the beginning of the project to understand the readiness and willingness of the functional groups to adopt agile approaches. Organizational culture is the set of shared values, beliefs, and norms that influence the way people think, feel, and behave in an organization. It affects the project management style, communication, stakeholder engagement, and change management. By assessing the organizational culture, the project manager can identify the potential barriers and enablers for agile transformation, and plan appropriate strategies to address them. For example, the project manager can provide training, coaching, mentoring, and feedback to the functional groups to help them understand and embrace the agile values and principles. Circulating the project charter (option A) is a good practice, but it does not ensure that the functional groups are prepared and supportive of the agile approaches. Determining the level of maturity of the employees (option C) is a useful input, but it does not capture the whole picture of the organizational culture. Communicating the project schedule (option D) is also important, but it does not address the underlying reasons for the pushback from the functional groups. References:
* PMBOK Guide, 6th edition, page 30-31, section 2.2.2 Organizational Culture
* [Agile Practice Guide], page 16-17, section 2.1.2 Organizational Culture
* PMP Exam Prep, 10th edition, page 435, question 435, answer and explanation

The project manager should use a hybrid model to combine predictive and adaptive life cycles. This approach allows for the initial planning and structure of the predictive approach while also incorporating the flexibility of the adaptive approach to respond to changes and new information. The hybrid approach is beneficial in scenarios where the project has clear phases but also requires adaptability to changing requirements and inputs from stakeholders.
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PMBOK Guide - Seventh Edition: Covers all development approaches including predictive, adaptive, and hybrid1.
Introduction to Adaptive Project Management: Emphasizes the importance of adapting to changes and learning from outcomes2.
Predictive & Adaptive Project Management: Discusses when to use predictive and adaptive approaches3.
Hybrid Project Management: Explains the hybrid approach as a combination of high-level planning with the waterfall approach and execution with Agile methods4.

In a global project with team members dispersed across different countries, it's crucial to foster engagement and collaboration. Forming a core group of team leads representing members from each country can help facilitate communication and collaboration1. This approach can help address cultural differences and time zone challenges, and ensure that all team members feel represented and heard.
Asking team members to agree on a meeting time prior to setting up virtual meetings can help accommodate different time zones and ensure that all team members can participate2. This approach respects the time of all team members and can help improve attendance and punctuality at meetings.
Establishing virtual one-on-one's with team members to address any issues and/or concerns privately can help the project manager understand individual challenges and provide tailored support3. This approach can help build trust, improve communication, and ultimately, enhance team engagement4. References: PMI Global Congress 2015-North America, APM, BrightWork.com, LoopinHQ

The project manager should describe to the team members how specific tools and techniques can be used to finish on time, as this will help them understand the rationale behind the rigorous process and how it can benefit the project. This will also demonstrate the project manager's respect for the team's expertise and autonomy, and foster a collaborative and supportive environment. The other options are not as effective or appropriate as describing the tools and techniques to the team. Crashing the project schedule and asking the team to work overtime may increase the risk of errors, burnout, and resentment. Motivating the team by offering incentives may not address the root cause of the resistance, and may create a sense of coercion or manipulation. Convincing the team to use a specific methodology may not be feasible or suitable for the project, and may undermine the team's self-organization and creativity. References:
* PMBOK Guide, 7th edition, page 249
* PMI-PBA Exam Content Outline, 2018, page 11

According to the PMI, a hybrid approach is a combination of two or more project methodologies, such as waterfall and agile, to suit the needs of the project. A hybrid approach can offer flexibility, adaptability, and customer focus, while also maintaining some level of predictability, structure, and control. However, a hybrid approach can also pose some challenges, such as stakeholder resistance, misalignment, or confusion.
Therefore, the project manager needs to address and remove any obstacles and blockers that may prevent the team from achieving their goals. Obstacles and blockers are issues or impediments that hinder or stop the team's progress, such as lack of resources, unclear requirements, technical debt, conflicts, communication gaps, etc. The project manager should follow these steps to address and remove obstacles and blockers for the team:
* Identify the obstacles and blockers by using various techniques, such as daily stand-up meetings, retrospectives, feedback sessions, surveys, etc.
* Analyze the impact, root cause, and priority of the obstacles and blockers by using tools, such as issue logs, risk registers, impact analysis, root cause analysis, prioritization matrix, etc.
* Develop and implement solutions to remove the obstacles and blockers by using methods, such as problem-solving, negotiation, escalation, delegation, collaboration, etc.
* Monitor and evaluate the effectiveness of the solutions by using measures, such as team velocity, customer satisfaction, quality metrics, etc.
* Communicate and report the status and results of the solutions to the relevant stakeholders, such as the team, the sponsor, the customer, etc.
By addressing and removing obstacles and blockers for the team, the project manager can improve the project performance, as well as the team's productivity, quality, morale, and collaboration.
The other options are not the best choices, because:
* Asking stakeholders to communicate with the project manager and not directly with the team would create a communication bottleneck, reduce transparency, and increase the risk of misunderstanding or miscommunication.
* Empowering the team members to remove obstacles and blockers would be a good practice, but it would not be sufficient without the project manager's support, guidance, and intervention, especially if the obstacles and blockers are beyond the team's authority or capability.
* Adding blockers to the issue log and risk management plan would be a necessary step, but it would not be enough without taking action to resolve them. Simply documenting the blockers would not help the team to overcome them or improve their performance. References:
* Hybrid Project Management: What is it, Methodology & Software - Teamhood
* Agile, Traditional, and Hybrid Approaches to Project Success
* Impediments, Obstacles, and Blockers: How to Address and Remove Them
* 1.7. Address and remove impediments, obstacles, and blockers for the team - KnowledgeMap
* 1.7 Address and Remove Impediments, Obstacles, and Blockers ... - BrainBOK