Which of the following is true regarding the use of a smartphone while driving?

Answer: B — It is illegal to use unless mounted

Using a smartphone while driving carries specific regulations to ensure safety on the road. The statement that it is illegal to use a smartphone unless it is mounted reflects California’s laws designed to minimize distractions for drivers. Under these laws, drivers are allowed to use their phones only if they are hands-free or anchored in a mounting device, which helps keep the driver's attention on the road. The other options suggest misunderstandings about the regulations. For instance, while navigation apps can be useful, they are not exempt from the laws regarding smartphone use unless they meet the hands-free requirements. The notion that you may use your phone freely in traffic fails to account for safety and legal restrictions aimed at preventing distractions. Additionally, Bluetooth usage is generally not restricted, as it is often considered a hands-free method; thus, using a phone via Bluetooth is permissible as long as it does not involve any manual handling of the device. Understanding these laws helps ensure the safety of all road users while promoting responsible driving behavior.