A vessel "restricted in her ability to maneuver" is one which __________.

The definition of a vessel "restricted in her ability to maneuver" is specifically tied to the operational limitations imposed on a vessel due to its work or conditions it faces. A vessel that is restricted in its ability to maneuver cannot take the necessary actions required by the maritime navigation rules due to certain conditions, such as when its ability to deviate from its course is hindered because it is engaged in tasks like diving operations, laying pipelines, servicing navigation marks, or other similar activities.

This context makes it clear that the correct answer aligns with the established definitions in the International Regulations for Preventing Collisions at Sea (COLREGs) and the U.S. Coast Guard regulations. The other choices do not capture the essence of what it means for a vessel to be "restricted in her ability to maneuver." For example, simply being unable to maneuver as required does not cover the specific reasons a vessel might be restricted. Likewise, being limited in speed, under tow, or anchored in a busy channel describes other scenarios that do not encompass the specific operational restrictions that classify a vessel under this particular term.