What is major depressive disorder?
a. a disorder characterized by symptoms that do not interfere with a person's ability to work, sleep, study, eat, and enjoy once-pleasurable activities
b. a disorder that is enabling and helps a person function normally
c. a disorder characterized by depressive symptoms that are long-term but less severe than those of major depression
d. a disorder characterized by symptoms that interferes with a person's ability to work, sleep, study, eat, and enjoy once-pleasurable activities?
