Two navigational hazards are located near to each other, but each is marked by an individual cardinal buoyage system. The buoys of one cardinal system may be identified from the other system by __________.

Correct Answer: Option B — the difference in the periods of the light

When multiple cardinal systems are in proximity, the light period is the primary distinguishing feature. Each buoy in a cardinal system flashes at a specific rate to indicate its quadrant; varying these periods prevents confusion between adjacent hazards, ensuring mariners correctly identify the safe water side of each obstruction.