What Characteristics Place These Animals in the Same Group

What characteristics place these animals in the same group?

A) moist skins, eggs with a jelly-like coating, lungs in their adult forms, and gas exchange through their skin
B) internal fertilization, cartilaginous skeletons, and four-chambered hearts
C) ventral nerve cords and gills in their adult forms
D) shelled eggs, four-chambered hearts, and endothermic
E) cartilaginous skeletons, placental development, and internal fertilization