Which vehicle employment option positions the fire support vehicle on terrain to maximize the use of the laser designator and rangefinder while the FSO rides in the commander's vehicle?

The correct choice highlights the strategy of positioning the fire support vehicle in a manner that best utilizes the laser designator and rangefinder capabilities. In the observation option, the fire support vehicle is oriented specifically to take advantage of its optical and targeting systems effectively, allowing it to identify and designate targets accurately.

This setup allows the Fire Support Officer (FSO) to leverage the vehicle's advanced technology while remaining mobile in a separate commander's vehicle. By doing so, the FSO can maintain oversight of the broader operational context and coordinate fire support without being encumbered by the limitations of the fire support vehicle's position. This method enhances operational effectiveness in targeting and supporting maneuver units on the battlefield.

In contrast, the other choices represent strategies that do not prioritize the optimal positioning of the fire support vehicle in relation to observing and designating targets, thereby reducing effectiveness in managing fires and assessing the battlefield situation.