INLAND ONLY Your vessel must remain in a narrow channel for safe operation. Another vessel is crossing the channel from your starboard. You do not think she will pass safely. You MUST take which action?

Correct Answer: Option C — sound the danger signal

Rule 34(d) and Inland-specific provisions require sounding the danger signal (at least five short and rapid blasts) when doubt exists regarding the intentions or safety of another vessel crossing a narrow channel.