Since Jack's Forced Retirement, He Has Experienced Overwhelming Sadness and Has

Since Jack's forced retirement, he has experienced overwhelming sadness and has withdrawn from his friends and family. He has gained twenty pounds and has been sleeping much more than usual. Most noticeably, he is no longer interested in participating in his life-long hobby of playing several rounds of golf each week. Most likely Jack is experiencing

A) a fugue reaction.
B) bipolar disorder.
C) conversion disorder.
D) major depressive disorder.