Concept:Sphenopsida is a taxonomic class that includes horsetails and is placed within the group of vascular, non-seed plants.Explanation:Sphenopsida (horsetails) are characterized by jointed stems, scale-like leaves, and spore reproduction. They do not produce seeds or flowers. This places them in the division Pteridophyta along with ferns and other seedless vascular plants. Bryophytes, angiosperms, and gymnosperms lack these characteristic features.Answer:A. pteridophytes
