According to the PMBOK Guide, a project manager is responsible for leading and motivating the project team and ensuring their engagement with the project. A project manager should create an environment that encourages leadership, translates ambitions into growth opportunities, and rewards overtime workers when working with a project team composed of recent university graduates. This will help to inspire, empower, and recognize the team members, and to align their personal and professional goals with the project objectives.
Creating an environment that encourages leadership, translates ambitions into growth opportunities, and rewards overtime workers is the best action that the project manager should take in this situation. Providing clear direction on the work to be done and its alignment to the major objectives of the organization, using technology to communicate (A) may be a necessary action, but not sufficient to ensure the team's engagement, as it may not address their needs, interests, and expectations. Establishing a clear hierarchical environment and allowing them to navigate through the project faster using social networks (B) may not be effective or appropriate, as it may create a rigid or bureaucratic structure, and undermine the team's collaboration and communication. Fostering proactive decision making and developing a hierarchy to approve decisions based on different levels of complexity may be a good practice, but not the best one, as it may not create a conducive environment for the team's development and growth. References: PMBOK Guide, 6th edition, pages 349-350, 361-362.