Which of the following is considered a distracted driving behavior?

Distracted driving behaviors are activities that divert attention away from driving. Adjusting the radio while driving is a prime example of such a behavior. This action takes the driver's focus away from the road, as they must shift their attention to locate and manipulate controls, which can lead to slower reaction times and increased risk of an accident.

The other options represent behaviors that either do not distract the driver as significantly or are not inherently considered distractions. Looking at the road is fundamental to safe driving, while using hands-free devices is designed to minimize distraction compared to handheld device use. Eating snacks, while potentially distracting, does not necessitate as much attention away from the road as adjusting the radio does. Thus, adjusting the radio is clearly a more pronounced distraction, making it the correct choice in this context.