Question 910 Rules of the Road

The correct answer is D) Five short and rapid blasts of the whistle. This signal indicates doubt that sufficient action is being taken by another vessel to avoid collision, as per the International Regulations for Preventing Collisions at Sea (COLREGS) and the Inland Navigation Rules. The five short and rapid blasts of the whistle are a warning signal to alert the other vessel that immediate action may be necessary to avoid a collision. The other options are incorrect because they do not specifically indicate doubt about the other vessel's actions. Option A (three long blasts) is the signal for a vessel in distress, while options B (one prolonged blast followed by three short blasts) and C (three short and rapid blasts) have different meanings in the rules.