The correct answer is losing a loved one in an accident. Depression is different from sadness, sadness is an emotion that tends to be short lived and is the consequence of something that has happened that the person will deal with in a reasonable amount of time so not getting the desired prom dress or not being allowed to go out with friends would lead to sadness. Losing a loved one in an accident could lead to depression. Depression is chronic, it doesn't go away within a day or two, it lasts and can be the result of a tragic event in ones life. It is not just intense sadness, it is loss of motivation, loss of concentration, loss of energy, loss of interest in life.