Which group of arthropods includes insects, arachnids, centipedes, and crustaceans?

The correct answer encompasses all arthropods, which is indeed the broadest classification including insects, arachnids, centipedes, and crustaceans. Arthropods are characterized by their jointed limbs, exoskeleton made of chitin, and segmented bodies, and they represent the largest phylum within the animal kingdom.

This category allows for the inclusion of diverse groups such as insects (which fall under the class Hexapoda), arachnids (which include spiders and scorpions), crustaceans (like crabs and shrimp), and myriapods (such as centipedes and millipedes). In recognizing all arthropods as a cohesive group, one can appreciate their varied forms and functions, as well as their evolutionary significance.

The other options represent subsets of the arthropod phylum. Hexapods specifically refer to insects, the myriapods are distinguished by their many legs such as in centipedes and millipedes, while crustaceans refer to aquatic arthropods. Each of these options is too narrow to encompass the entirety of the arthropod group. Thus, the comprehensive answer that includes all these classifications is the correct choice.