What should a driver do if they're unsure whether it's safe to change lanes?

Answer: C — Be patient until it's safe to change

If a driver is unsure whether it's safe to change lanes, being patient until it's safe to do so is the most prudent approach. Taking the time to assess the situation reduces the risk of collisions and enhances overall road safety. Patience allows the driver to look for clear gaps in traffic and to ensure that it is indeed safe to make the maneuver, rather than rushing into a potentially dangerous situation. This strategy aligns with safe driving practices that prioritize awareness and caution over speed. It reflects the principle that if there is any doubt about safety, it is better to wait rather than acting quickly without sufficient information. This mindset helps to promote a culture of defensive driving among all road users.