To what precision must an observer be able to self-locate without navigational aids?

The correct answer is based on the requirement for an observer to determine their location accurately without the use of navigational aids. The precision of 10 or 100 meters indicates a level of accuracy that is generally acceptable for field operations and is often necessary to ensure effective communication and coordination in military contexts.

Self-locating within a margin of 10 or 100 meters allows for adequate situational awareness while minimizing the risk of errors that could affect mission outcomes. This precision strikes a balance between the need for accuracy and the practical limitations of self-location techniques that may rely on observable landmarks or estimates in field conditions.

The other choices either suggest a level of precision that is too broad or inadequate for effective operational effectiveness. For instance, the ranges provided in some options would not yield the operational effectiveness required in precise artillery targeting or coordination with other units.