This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
All of the following are Bipolar disorders except 
Select and explain. 
A. Mania + Depression, B. Hypomania + Depression, C. Mania alone, D. Depression alone
D: Depression alone
Answer: D: Depression alone 
Explanation: Even a single episode of Mania alone is considered as bipolar disorder.
Hence option 4 is false.