You must place a child in an approved child seat if the child is

a. three years of age and under.

b. under nine years of age.

c. under 60 pounds.

The answer is letter b, under nine years of age. It is because children who are nine and below tend to be really playful and if they are not seated on the approved child seat, they would likely do things that could cause them harm if the car is ever caught up in an accident or in some conditions. It is best to put them in an approved child seat for their own safety.

Yes all of them are right