How often should you check your mirrors while driving?

Answer: C — Every 10 seconds

Checking your mirrors regularly while driving is crucial for maintaining awareness of your surroundings and potential hazards on the road. Option A, checking every 5 minutes, is not frequent enough and could lead to a missed hazard or changing road conditions. Option B, automatically, implies that you do not need to actively check your mirrors, which is not recommended. Option D, once in a while, is too vague and does not provide a specific time frame for checking your mirrors. Therefore, the most appropriate and safest answer is to check your mirrors every 10 seconds while driving.