Since Jack's forced retirement, he has experienced overwhelming sadness and has withdrawn from his friends and family.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 .

Major depression

Explanation:

Major depression is the type of severe depression in which a person tends to feel despaired and sense of sadness majorly. Symptoms of this depression tend to last long as it is severe condition .Person experience anxiety non-enjoyable feeling in enjoyable acts,irritation, weight gain etc.

According to the question,Jacks is experiencing major depression as he is profoundly sad and in despair.He is not interested in playing golf which gave him happiness along with gaining more weight.

c. wright mills's sociological imagination suggest investigating to explain this increase?