The law requires that all children under the age of ________ wear appropriate safety restraints.

Answer: D — 15

In Arkansas, the law requires that all children under the age of 15 wear appropriate safety restraints while in a motor vehicle. This is because children under the age of 15 are considered to be at a higher risk of injury in the event of a car accident if not properly restrained. It is crucial to ensure the safety of young passengers by using age-appropriate car seats, booster seats, or seat belts as required by law. Therefore, option D (15) is the correct answer.