Which of the following is an arachnid?

An arachnid refers to a type of arthropod, an invertebrate animal with an exoskeleton and jointed limbs. This includes spiders, scorpions, ticks, and mites. Option A, Antidote, is a substance used to counteract the effects of poison. Option B, Attractant, refers to something that attracts or lures. Option C, Avicide, is a substance used to kill birds. Only option D, Arachnid, is a correct answer and fits the definition of an arachnid.