What structure does 'arachnoid' refer to in the context of Venus?

The term 'arachnoid' in the context of Venus refers to a type of landform that resembles a spider web. This unique geological feature is characterized by a network of intersecting ridges that create patterns similar to a web, indicating that the surface has undergone complex tectonic processes. Such structures are believed to be associated with the rise and fall of the planet's crust, and the term 'arachnoid' is derived from the word 'arachnid,' which relates to spiders, highlighting the web-like appearance of these formations.

This choice reflects an understanding of how surface features on Venus are categorized based on their physical characteristics, particularly their intricate designs that are visually reminiscent of spider webs. The other options, while plausible in a different context, do not accurately describe the arachnoid landforms found on Venus.