Which term describes a type of operation that mainly provides early warning to friendly forces?

The term that best describes a type of operation focused on providing early warning to friendly forces is the one associated with screening. A screening operation is designed to detect and report any enemy activity, thereby ensuring that friendly units remain informed of potential threats. The primary function of a screen is to establish a buffer zone where the presence of enemy forces can be detected early, allowing friendly troops to prepare and respond accordingly.

This proactive measure is crucial for maintaining situational awareness and ensuring combat readiness, particularly in dynamic operational environments. By employing a screening operation, units can monitor enemy movements, gather intelligence, and relay that information back to command—which enhances overall operational security and effectiveness.

In contrast, the other options refer to different operational roles. For instance, securing involves protecting a specific area or assets, suppressing implies reducing the effectiveness of enemy forces typically through direct combat, and supporting by fire refers to providing firepower to assist another unit's maneuver, but does not inherently focus on early warning capabilities. Therefore, the emphasis on early detection and reporting makes screening the correct answer in this context.