Answer:
First, we need to find the total number of possible routes they can have. They want four possible routs about 47 states.

Therefore, there are 4,280,760 ways to select four routes.
The probability of having only one route is

Additionally, it's not practical at all to list all different routes and selec the best one, because there are too many, if they listed all routes, the campaign will be over by then.