Final answer:
Beth is most likely experiencing Bipolar disorder, which is characterized by extreme mood swings with episodes of mania and depression that impair daily functioning. The correct answer is option C.
Step-by-step explanation:
Beth is most likely experiencing C. Bipolar disorder. This condition is defined by extreme mood swings, which include one or more episodes of mania and typically depressive episodes, that significantly impair one's ability to function in daily life.
These mood swings can manifest as manic episodes characterized by an abnormally elevated mood, increased activity, and energy that last for at least one week. On the flip side, depressive episodes involve feeling intensely sad, losing interest in activities, and experiencing changes in appetite and sleep schedules, among other symptoms.
Considering that about 10 percent of U.S. adults are likely to be affected by mood disorders annually, with a lifetime prevalence of 21 percent, Beth's condition is not uncommon. It is essential to distinguish bipolar disorder from major depression, which consists solely of depressive episodes without manic phases.