What feature does a permanently placed daymark have?

A permanently placed daymark is a navigational aid designed to indicate specific points or navigable channels on water. It is primarily intended for daytime visibility and navigation without providing light, which is why it may or may not be lit. Daymarks often consist of reflective materials or distinctive colors and shapes to help mariners identify their location and the routes they should take.

Since a daymark is designed to function during the day, it doesn't necessarily have a light source, making the answer that it may or may not be lit correct. Recognizing that permanent daymarks are static and non-movable is crucial when considering navigational safety. The other options would imply characteristics that are not inherent to permanent daymarks. For instance, they are not always lit, since their primary purpose does not include illuminating darkness, nor are they intended purely for recreational purposes, as their main function is to aid navigation.