Which of the following examples would be considered a natural monument?

The concept of a natural monument refers to significant natural features that are typically recognized for their environmental, geological, or ecological importance. Trees and rocks exemplify natural monuments as they embody natural formations that have developed over time and often hold cultural or historical significance as well. For instance, a giant redwood tree or a unique rock formation can be seen as a monument to nature’s artistic and historical processes, attracting attention and appreciation from both locals and visitors.

In contrast, the other options listed are man-made or artificial constructs. Metal pins and concrete markers are tools or materials created by humans and do not arise from natural processes, whereas roads and fences are infrastructure that facilitates human movement and property delineation. Therefore, they do not fit within the definition of a natural monument, which emphasizes the intrinsic value and significance of naturally occurring features.