For the Past 3 Weeks,the Nurse Has Observed a Patient

For the past 3 weeks,the nurse has observed a patient interacting with staff and other patients,helping decorate the dining room for a party,and leading the singing in the activity room.Today,the patient tearfully refuses to dress or get out of bed.The nurse recognizes these behaviors as evidence of:

A) unipolar depression.
B) dysthymic disorder.
C) hypomanic episode.
D) bipolar disorder.