Final answer:
It is illegal to pass if you are closer to an intersection or railroad crossing than 100 feet.
Step-by-step explanation:
According to traffic laws, it is illegal to pass if you are closer to an intersection or railroad crossing than 100 feet (option c). This distance is determined to ensure the safety of all drivers by allowing enough space for vehicles to stop or yield when necessary.
If a driver is closer than 100 feet to an intersection or railroad crossing, they should not attempt to pass another vehicle as it can be dangerous and increase the risk of accidents or collisions.
For example, if a driver is 90 feet away from an intersection and tries to pass another vehicle, they may not have enough time to stop if a traffic light changes or a train approaches the crossing.