How Useful Are the Concepts of 'Risk' and 'Protective' Factors

How useful are the concepts of 'risk' and 'protective' factors?

A) They enable us to understand that there are wide individual differences in children's responses to stress and adversity
B) They enable us to understand that stressful events have a common effect on all children
C) The concepts of 'risk' and 'protective' factors are not useful
D) It is more useful to consider the financial circumstances of the child's family