PART A: What is the author's purpose in this text? A to bring attention to a new understanding of how social problems
behave and how they might be improved
B to encourage conservative politicians not to cut funding on projects
that don't appear to be working
C to remind people of the influences that tipping points have on social
problems so they can prevent them from happening
D to reassure people that most social problems don't need interference
and will eventually resolve themselves