What characteristic of the trophy rock helps attract deer?

The trophy rock's salt content is a key characteristic that helps attract deer. Deer require salt and other minerals for their overall health and well-being, particularly during certain times of the year when they may be lacking these nutrients in their natural diet. The salt in the trophy rock acts as an attractant because it provides a source of sodium, which is essential for various bodily functions in deer. Such mineral blocks or rocks are often utilized by hunters to draw deer into specific areas, as the animals are naturally inclined to seek out sources of salt in their habitat. This behavior makes the trophy rock with its high salt content an effective tool for attracting deer while also helping to support their nutritional needs.

Other options, like color, size, and shape, might influence visibility or palatability to some extent, but they do not have the same physiological allure for deer as the salt content does.