At ups, delivery vary according to whether a route is urban, suburban, or rural in nature, because conditions vary in each type of route.

I believe the correct answer is: standards.

At UPS, delivery standards vary according to whether a route is urban, suburban, or rural in nature, because conditions vary in each type of route. The standards, established by UPS, for drivers are set projections for the number of miles driven, deliveries, and pickups, but they may vary depending on the route.