Over the Last Three Months,Regina's Feelings of Despair Have Intensified

Over the last three months,Regina's feelings of despair have intensified for no apparent reason.Although her friends have tried to be encouraging and supportive,Regina says that she feels worthless and completely detached from people,and she has even thought about killing herself.Regina's symptoms would suggest that she is probably suffering from

A) mania.
B) bipolar disorder.
C) major depressive disorder.
D) disruptive mood dysregulation disorder.