INLAND ONLY Two power-driven vessels are crossing within a half a mile of each other as shown in illustration D042RR below. Vessel "A" sounds one short blast on the whistle. What should Vessel "B" sound?

Correct Answer: Option B — one short blast

33 CFR 83.34(a) mandates that power-driven vessels in sight of one another and meeting or crossing at a distance within half a mile must exchange sound signals. Since Vessel A initiated a one-short-blast signal for a port-to-port passing, Vessel B must respond with one short blast to indicate agreement.