Final answer:
An executive in project planning and execution collaborates with team members and stakeholders, not typically with alumni associations or CDs, unless the project is specifically related to those areas.
Step-by-step explanation:
An executive overseeing all aspects of project planning and execution will most likely collaborate with members of their team, which can include a variety of stakeholders such as project managers, team leaders, and individual contributors. Alumni associations and CDs (Certificates of Deposit) are generally not directly involved in project planning and execution unless the project is directly related to alumni engagement or financial investments. Therefore, the most appropriate collaboration would be with members (c) who are directly involved in the project.