What equipment would be most useful for communicating messages in low-light conditions?

The correct choice is light wands because they are specifically designed to enhance visibility in low-light conditions. Light wands typically emit bright, easily noticeable light, making them effective for signaling and communication when visibility is limited. Their glowing or flashing nature can attract attention and convey messages clearly even when ambient light is low, which is crucial for safety and coordination in various environments.

In contrast, the other options do not serve the purpose of communication effectively in such conditions. Drift pins and marline spikes are tools primarily used for heavy lifting and splicing rope, not for signaling. Goggles, while useful for vision protection or enhancement in certain situations, do not provide any means of communication or signaling.