The correct answer is C. David feels sad for a long period, even when something good happens
Step-by-step explanation:
In general terms, mental health professionals are required when individuals experience mental health problems that are characterized by an inability to control behavior or emotions, self-destructive thoughts or behaviors, violent or abnormal reactions, excess of negative feelings, among others.
This implies, the scenario that requires attention from mental health professional is "David feels sad for a long period, even when something good happens" because in this case there is an excess of negative feelings and thoughts that are not being triggered by any situation which is not normal and shows a mental health issue such as depression. Also, in other scenarios, specific feelings are triggered by situations and they last only a short time which is a normal reaction.