What Does the Duty to Mitigate Require of an Employee

What does the duty to mitigate require of an employee whose position has been constructively terminated?

A) The employee could be required to accept a lower position in the same company.
B) It requires the former employee to take reasonable steps to find comparable employment.
C) The individual is expected to accept a lower-level job in another company to reduce loss.
D) It requires the former employee to take the first job available.