Answer: A. MAJOR DEPRESSIVE DISORDER
Explanation: Major Depressive disorder is a disorder directly connected with the MOOD of individuals,it is Characterised by a persistent SADNESS LASTING LONGER THAN NORMAL( 2 weeks or more) it has also been described as CLINICAL OR MENTAL DISORDER.
Major Depressive disorder (DEPRESSION) affects the normal functions of the body by Altering the Hormonal system, Cell related activities etc. It is the major cause of MENTAL DISORDER IN THE UNITED STATES according to several Reports.