What does the "P" signifier indicate when present in the RVR group?

The "P" signifier in the RVR (Runway Visual Range) group is used to indicate that the observed RVR is above the maximum value that the system can measure. This typically occurs in conditions where visibility is exceptionally clear, such as during fine weather with little to no obstructions. The presence of "P" means that the specific RVR measurement cannot be accurately provided because it exceeds the upper limit of the range that the equipment can report.

In the context of the other options, the meanings differ significantly. If the observed RVR were below the minimum value, that situation would likely be indicated without the "P" signifier. A standard value would also not include the "P," as it indicates a typical RVR range. Fluctuating RVR readings would be noted in a different manner and not designated with "P." Thus, the presence of "P" specifically denotes that the RVR measurement is extraordinarily high, reinforcing that "C" is indeed accurate.