What lights or shapes are required for a vessel under 12 metres when aground?

For a vessel under 12 meters in length, there is no requirement to exhibit lights or shapes when aground, which makes this option the correct choice. According to the COLREGs, smaller vessels have different requirements compared to larger vessels, specifically when it comes to lights and shapes, due to considerations of practicality and safety.

Vessels under 12 meters are typically not required to display the same navigational aids as larger vessels, simplifying their operation and recognizing the limitations of smaller crafts in various conditions. The principle behind this exemption is to reduce the regulatory burden on smaller vessels while maintaining safety standards.

In the context of the other choices, vessels that exhibit anchor lights and shapes, or that need to show a single white light or shapes for vessels over 12 meters, do not apply here because those regulations specifically cater to vessels that are larger and more complex in terms of navigation and safety requirements. Thus, for smaller vessels aground, the absence of a requirement to display any lights or shapes is a simplification that still upholds the overall navigational safety framework.