Final answer:
Postpartum hypomania has low incidence rates and often resolves without leading to further complications such as psychosis or chronic depression.
Step-by-step explanation:
The incidence rates of postpartum hypomania are generally considered to be low. This condition frequently resolves without further complications, aligning with option d) Low incidence rates; often resolves without further complications. Postpartum hypomania can be an indicator of underlying mood disorders, but it does not frequently lead to psychosis or chronic depression. In some cases, it might be associated with bipolar disorder, especially when hypomanic episodes precede or follow major depressive episodes, but again, postpartum hypomania typically resolves without progressing to a more severe mood disorder.