Which action is known to reduce speeding in teens?
a. better roadways
b. drinking alcohol
c. peer actions
d. other drivers' speeding

It would be C. 

A would not be it because even if you have better roadways they may not help reduce the speed and instead increase it because the teen may like the smooth feeling.

B would not be it because the driver is under the influence. This usually can put the idea of going really fast in the driver's mind because "who would stop them?" and "what's the worst that could happen?"

D would not be it because the teenager may want to compete with the other driver to become victorious which would include in them speeding up.

Answercapillaries;

Answer in 2009 barack obama signed into law the family smoking prevention and tobacco control act, the new law (h.r.   1256) represents the most sweeping action taken to date to reduce what remains the leading preventable cause of death in the united states;