You are approaching the first of two drawbridges that span a narrow channel. The second drawbridge is close to the first. Which signals should you sound?

Correct Answer: Option D — Sound the request-for-opening signal and, after the bridge acknowledges it, sound the request-for-opening signal for the second bridge.

When approaching multiple drawbridges in close succession, standard bridge signaling requires sounding the request-for-opening signal for the first bridge, waiting for acknowledgment, and subsequently sounding the signal for the second bridge to ensure safe coordination.