After teaching a group of parents of preschoolers attending a well-child clinic about oral hygiene and tooth brushing, the nurse determines that the teaching has been successful when the parents state...

After teaching a group of parents of preschoolers attending a well-child clinic about oral hygiene and tooth brushing, the nurse determines that the teaching has been successful when the parents state that children can begin to brush their teeth without help at which of the following ages?

1. 3 years.

2. 5 years.

3. 7 years.

4. 9 years.