Answer:
B) willingly accept end dates dictated by customers or sponsors
Step-by-step explanation:
Usually when a project manager faces serious schedule challenges, it is because the schedule was not properly determined, something went wrong and was significant enough to delay the whole schedule, or the schedule was extremely tight on purpose.
When the project manager is facing serious challenges or problems, the last thing he/she should do is accept dates imposed or dictated by customers or sponsors. He/she is already facing serious challenges and there is no reason why those challenges should increase.
What he/she should do is elaborate a schedule that can be completed on time and then persuade the stakeholders that this is the best possible schedule in terms of a cost-benefit analysis.