The correct option is
D All of the above
Urochordate animals show all three characters, like neoteny, retrogressive metamorphosis and paedogenesis. Neoteny is the phenomenon whereby an organism retains larval characteristics, when sexually mature and most likely occurs by mutation, in the course of evolution. They only reproduce sexually and produce tadpole-like larvae that are free-swimming and metamorphose into the adult in the water column. The larvae possesses advanced features like the notocord. The features are lost while the development of the larvae to form an adult. This type of metamorphosis in which there is retrograde loss in the features of the larvae is called as retrogressive metamorphosis. Paedogenesis is the act of reproduction by an organism that has not achieved physical maturity. Thus, the correct answer is option D.