When is it permissible to use a mobile phone while driving?

Using a mobile phone while driving is permissible when using a hands-free system. This option allows drivers to keep their hands on the wheel and their eyes on the road, thus maintaining attention to driving while engaging in phone conversations. Hands-free systems can include Bluetooth devices, integrated car systems, or other technology that allows voice commands to minimize distraction. It's important to remain focused on the driving task, and hands-free options enable communication without significantly diverting attention from the road.

The other options present situations that are not compliant with safe driving practices. For instance, using a mobile phone while stopped at a red light could still lead to distraction and isn't a safe or responsible practice, as it encourages drivers to engage with their devices instead of being alert to their surroundings. While rural roads might seem less congested, the rules regarding mobile phone usage while driving still apply to ensure safety, as distractions can still lead to accidents. Lastly, the option stating that mobile phones should never be used while driving reflects a broad precaution that emphasizes the importance of avoiding any form of distraction which is a best practice for drivers.