Final answer:
The project manager must make trade-offs between different functions in project management, such as technical and interpersonal, planning and execution, and cost and quality.
Step-by-step explanation:
The trade-offs involved in project management often require the project manager to make decisions between project progress and process. This involves trade-offs between the technical and interpersonal functions (a), as the project manager needs to balance the technical aspects of the project with the management of the team and stakeholders.
Another trade-off is between planning and execution (b). The project manager needs to allocate time for careful planning and organization, while also ensuring that the project is progressing and tasks are being executed efficiently.
One more trade-off is between cost and quality (d). The project manager needs to find the right balance between keeping the project within budget and delivering a high-quality end result.