C. Encourage your passengers to loosen up to make their ride more enjoyable.
Explanation:
C. because if you encourage them to "loosen up", something might happen, like a car accident or it's raining or snowing and you may be going a bit fast. You have to stay away from strangers, make sure you are around people you trust, and to tell your friends they shouldn't be bothering you so you can pay attention to the road.
