Ocean swells originating from a typhoon can move ahead of it at speeds near __________.

Correct Answer: Option D — 50 knots

Typhoon-generated swells travel outward from the storm center at high velocities, often exceeding the forward speed of the storm itself. Bowditch notes these precursor swells can propagate at speeds up to 50 knots, serving as a critical early warning sign of an approaching tropical cyclone in open waters.