Just Before the 2007 Daytona 500, NASCAR Heavily Fined Several

Just before the 2007 Daytona 500, NASCAR heavily fined several racing teams for using fuel additives that make cars go slightly faster. Why would NASCAR want to take steps to lower the speed of their race cars?

A) Like MLB with steroids, NASCAR fears that if they don't act to prevent the use of illegal substances, the federal government will step in instead to regulate their league.
B) NASCAR fans prefer relative quality over absolute quality.
C) Slower cars provide for significantly better track safety.
D) All of the above