Final answer:
The correct answer is 'True'. Most rear-end crashes are caused by the vehicle in back following too closely.
Step-by-step explanation:
The correct answer is a. True.
Most rear-end crashes are indeed caused by the vehicle in back following too closely. When a driver follows too closely, also known as tailgating, they have less time to react if the vehicle in front suddenly slows down or stops. This can result in a collision where the back vehicle crashes into the vehicle in front.
According to the National Highway Traffic Safety Administration (NHTSA), about 40% of all crashes are rear-end collisions caused by following too closely.