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 which psychiatric disorder?

A) Unipolar depression
B) Dysthymic disorder
C) Hypomanic episode
D) Bipolar disorder