These problems are mild in some cases and severe in other cases that may leads to serious problems with respect to their health, relation and also at work place. The two key moods involved in mood disorders are mania and depression. In mania they live in unrealistic feelings and excitement and in depression they are in sadness and dejection.
Hence the options a, b and c are not correct.
But in almost all cases there may be mixed –episodes of mania and depressions in a same course of illness.
Hence the correct option is .