Which indication may suggest that a risk of collision exists?

The indication that suggests a risk of collision is related to an approaching vessel with no change in bearing. When the bearing to another vessel remains constant, it implies that the two vessels are on a collision course. This is a crucial situation because it indicates that both vessels are moving towards each other and that action must be taken to avoid a collision.

Monitoring the bearing of another vessel is an essential practice in navigation. If a vessel is approaching with no change in its compass bearing, it means it is either moving directly towards the observer’s vessel or the observer's vessel is moving towards it, necessitating immediate attention and potential maneuvering to ensure safety.

In contrast, an appreciating change in compass bearing would suggest that the vessels are moving apart or at least not on a collision course. A stationary vessel does not present an immediate risk of collision since it is not moving, and a distant vessel, while it may be important for navigation awareness, does not indicate an immediate risk unless its vectors suggest otherwise.