Whether you ride on hectic city streets or bucolic [rural] back roads, helmets are essential armor. bicycle helmets have been shown to reduce the risk of head injuries by up to 88 percent and facial injuries by 65 percent, according to a cochrane database systemic review published in 2000. bike riders who play against those odds do not fare well in accidents. more than 90 percent of the 714 bicyclists killed in 2008 were not wearing helmets, according to the insurance institute for highway safety.

what is the overall tone of this excerpt?
a.) pushy
b.) hesitant
c.) carefree
d.)assertive