Question 210 Rules of the Road

The correct answer is D) vessel pushing ahead. The display of two yellow lights in a vertical line indicates that the vessel is pushing ahead another vessel, as per the Inland Navigation Rules (Rule 23). This signal is used to identify a vessel that is engaged in the process of pushing another vessel from behind, which is a common practice in inland waterways. The vertical arrangement of the lights helps to distinguish this configuration from other vessel lighting arrangements. The other answer choices are incorrect because they do not match the specific lighting configuration described in the question. A) opening in a pipeline and B) vessel broken down do not have any relation to the displayed lights, while C) vessel fishing would have different lighting requirements.