INTERNATIONAL ONLY When two vessels are in sight of one another and NOT in or near an area of restricted visibility, any of the following signals may be given EXCEPT which signal?

Correct Answer: Option B — Four short whistle blasts

Rule 34(d) specifies that the danger signal consists of at least five short and rapid blasts. Four short blasts is not a valid signal under the International Rules. The other options represent authorized signals for maneuvering, overtaking, or indicating doubt regarding the other vessel's actions.