What type of buoy marks the entrance to a channel?

The correct choice indicates that an "in" marker or a green buoy marks the entrance to a channel, which is vital information for safe navigation. In the United States, the buoyage system follows specific color codes and shapes that help boaters understand navigational aids.

Green buoys are typically associated with the right side of a channel when entering from the open sea or a larger body of water, and they mark the entrance leading into a channel. These buoys are also important because they help to demarcate safe navigable passages and indicate where to steer to remain clear of hazards. Understanding this system allows boaters to navigate safely and avoid running aground or hitting submerged obstacles.

Other options listed may serve different purposes; for example, a red buoy usually indicates the right side when leaving a channel and is not meant for approach. Yellow buoys generally provide informational signals and are not used for channel marking, while white buoys often indicate controlled areas or no-wake zones, which are also not directly involved in channel navigation. Recognizing the distinct roles of these markers is crucial for effective boating navigation and safety.