The Nurse Manager of a Unit Was Demoted to Staff

The nurse manager of a unit was demoted to staff nurse 6 months ago.Because of being near retirement,the former nurse manager wanted to be employed at the hospital and was offered a position on the same unit.The former nurse manager complains often about how infrequently the current nurse manager is available on the unit and argues with physicians and co-workers.Clients have complained about the attitude of the nurse.The behavior of the former nurse manager can be best explained as being caused by:

A) overwork in the staff nurse position.
B) inadequate mentoring in the new role.
C) anger as a stage of the grieving process.
D) demotion as a threat to personal identity.