Final answer:
Amniotes are vertebrates that originated during the Carboniferous period with terrestrially adapted eggs, which allowed them to lay eggs in dry places without the need to return to water for reproduction. The answer is option D.
Step-by-step explanation:
Vertebrates with well-protected eggs that can be laid in dry places that originated during the Carboniferous period are known as amniotes. These animals are distinct from amphibians due to the presence of terrestrially adapted eggs that are protected by amniotic membranes.
Amniotes include reptiles, birds, and mammals. They possess eggs with internal membranes that allow gas exchange but prevent the embryo from drying out, enabling them to reproduce on land without the need to return to water. This adaptation allowed for greater diversity in habitat and was a significant evolutionary milestone that distinguished them from amphibians, which must lay their eggs in water due to their lack of a protective covering.