A woman brings her 32- year- old husband to a psychiatrist for "unusual behavior". She says that for the past 5 days he has been cleaning the house extensively, often late into the night. He wakes up 2 hours earlier than usual the next morning but does not appear tired. He says he feels "very happy and productive- the best I have ever been!" His wife denies any dangerous behavior's at home and reports he is able to continue working at his current job, albeit more productively than before. She recalls that 6 months ago, he seemed very depressed, with loss of interest, poor sleep, low energy, and impaired concentration that lasted 1 month. The pt has not been hospitalized previously. On interview, he is pleasant and cooperative. His speech is pressured but redirectable. His thought process is linear, and he denies any hallucinations. His urine toxicology screen is negative. What is the likely diagnosis?

A. Bipolar I disorder.
B. Bipolar II disorder.
C. Schizophrenia.
D. Substance/ medication- induced bipolar and related disorder.