In which scenario is it illegal to use your phone while driving?

Answer: C — When texting and driving.

Using your phone while driving is illegal when texting and driving because it significantly distracts the driver from the task at hand. Texting requires visual, manual, and cognitive attention, which compromises the driver's ability to react to changing road conditions, other vehicles, and pedestrians. This type of distraction has been shown to increase the likelihood of accidents, making it particularly dangerous and illegal in many jurisdictions, including Washington State. Legislation is specifically aimed at reducing this risk by prohibiting texting while operating a vehicle, thus promoting safer driving practices. In contrast, using a phone when stopped at a red light, utilizing hands-free devices, or driving in rural areas may not carry the same legal restrictions and are generally permitted under certain conditions.