What distance should mortars be placed in relation to friendly units?

For the proper placement of mortars in relation to friendly units, maintaining a distance of one-half to two-thirds of their range ensures both safety and operational effectiveness. This distance minimizes the risk of friendly fire as it allows for a safe buffer zone while still enabling the mortars to effectively support ground troops with their firepower.

Positioning mortars within this specified range is crucial because it helps the operators to accurately engage targets while avoiding mishaps that could occur if they were too close. A distance of one-half to two-thirds of the mortar's effective range enables sufficient margin for error, accounting for factors like wind, angle of fire, and adjustment corrections.

The other options suggest either a too-close engagement with the units or excessive distance, which would hinder the ability to provide timely support. By choosing the correct range, units can maximize their operational efficiency while ensuring the safety of friendly personnel on the ground.