Which of the Steps in Systems-Thinking Is Illustrated in the Following

Which of the steps in systems-thinking is illustrated in the following example?
Pregnant women are highly motivated to stop smoking cigarettes, which benefits them as well as reducing the chances of a low-birth-weight child.

A) Identify key factors or influences that impact an outcome
B) Estimate the relative strength of each of the influences
C) Examine the interactions between factors
D) Identify bottlenecks
E) Identify leverage points