Final answer:
The project manager should persist in collaborating with stakeholders to gather requirements, using various communication methods when face-to-face meetings are not possible.
Step-by-step explanation:
When a project manager is encountering difficulties in collecting requirements from stakeholders who are unavailable for meetings, the best course of action would be to continue working with the stakeholders to collect the requirements. This can involve searching for alternative methods of communication such as emails, surveys, or setting up individual meetings to ensure adequate input for the scope of the project. Writing the requirements alone without sufficient input can lead to project failures or the need for substantial revisions later, which may incur additional costs and delays. Creating a scope statement based on incomplete requirements could result in an inaccurate project direction, and stopping the project might not be feasible and could lead to a loss of trust and support from those involved.