Unexploded ordnance found in the RTA must be reported to whom?

The correct answer is to report unexploded ordnance (UXO) to Range Control because this department is specifically responsible for the management and safety of munitions on the range. Range Control acts as the central authority in terms of safety procedures and environmental considerations within the range area. They have the necessary training and protocols to assess the situation, mitigate risks, and coordinate with other necessary agencies, ensuring a safe response to the discovery of UXO.

By reporting to Range Control, the proper assessment and action can be taken to secure the area and handle the ordnance safely. Other options, while relevant in different contexts, do not play the same direct role in managing unexploded ordnance on the range.