When using the ARPA in heavy rain, which action should you take?

Correct Answer: Option B — Navigate as though the effective range of the radar has been reduced.

Heavy rain causes significant attenuation of radar signals, effectively reducing the maximum range and clarity of target detection. Mariners must acknowledge this limitation by increasing situational awareness and navigating as though the radar's effective range is diminished, rather than relying on gain adjustments which may introduce excessive noise.