The child-safety seat comes in three types or sizes: The first type is designed for babies from birth to one year of age, until the baby weighs about 20 pounds; the second size is for children between one and four years of age, who weigh between 20 and 40 pounds; the third kind is used by older children big enough to use the car's belt system. Moreover, all these safety seats must be fitted and held in place on the car's back seat. If your child does need your attention while. you are driving, don't look back with only one hand on the wheel. Just pull over.
This text mainly discusses ______.

A. how a child-safety seat can protect a child
B. why the back seat is the safest place in a car
C. how a child can be kept safe while riding m a car
D. what causes passengers the most injuries