For a triangle placement in a two-lane undivided road situation, what is the distance from the front to the rear?

In the context of triangle placement on a two-lane undivided road, the correct answer identifies a measurement range that is appropriate for ensuring visibility and safety. The distance from the front to the rear should be sufficient to allow drivers to notice the emergency vehicle in time, contributing to accident prevention and ensuring clear passage for responding units and other vehicles.

The range of 100 feet to 10 feet implies a significant front space that allows vehicles to be positioned adequately while providing enough distance for visibility to approaching traffic. It supports the operational guidelines that address both safety for responders and the general public, as well as effective traffic control.

Other options either fall short in terms of distance or may not ensure adequate space for both the emergency response vehicle and general traffic, thereby compromising safety. The chosen range effectively balances the need for visibility with practical roadway considerations, making it the most suitable choice.