_____ is an unrelenting lack of pleasure in life.

A) Anxiety
B) Fear
C) Anger
D) Depression

Depression is characterized by a persistent lack of pleasure or interest in activities that would typically bring enjoyment. This symptom can be accompanied by other symptoms such as feelings of worthlessness, fatigue, and changes in appetite or sleep patterns. Anxiety, fear, and anger can all coexist with depression, but they are not the defining features of this mental health condition.