The correct option is A Instinct
An instinct is the ability of an animal to perform a behaviour the first time it is exposed to proper stimulus. The main reason spiders spin webs is to catch their food. When an insect, such as a fly, flies into a spider's web, it gets stuck on the sticky threads. When a spider catches prey in the sticky strands of its web, it approaches the trapped insect and uses its fangs to inject venom.