Which of the following sentences best describes type 2 bipolar disorder?
a. At least one manic episode and often accompanied by depressed or hypomanic periods.
b. Depressed mood co-exists with manic symptoms. Alternating periods of hypomania and periods of mild to moderate depressive symptoms over the course of two years.
c. At least one hypomanic episode, at least one major depressive episode, and absence of manic episodes.
d. One manic episode and one hypomanic episode.