Use this fact to answer the question: a decrease in visibility while driving can cause people to crash their car

Steve was driving on the highway when he rear-ended another car because he didn't see it until he was just a foot away. This could have happened because of

OPTIONS:
- reports of tornadoes in the area
- a dog running across the highway behind Steve's car
- a sudden fog moving into the area
- ice forming on the road
a sudden fog moving into the area