Select the vertebrate.

 - golden orb-weaver
 - trapdoor spider
 - Pacific octopus
 - echidna
Like other spiders, a golden orb-weaver is an invertebrate. It does not have a backbone. It has an exoskeleton.
Like other spiders, a trapdoor spider is an invertebrate. It does not have a backbone. It has an exoskeleton.
An echidna is a mammal. Like other mammals, an echidna is a vertebrate. It has a backbone.
Like other octopuses, a Pacific octopus is an invertebrate. It does not have a backbone. It has a soft body.