Answer:
The correct answer is option C. "reptiles".
Explanation:
The phylum Chordata, corresponds to all animals that posses a backbone. Among the different subphyla of animals classified as vertebrates, the birds are most closely related with reptiles. Phylogenetic studies have found that the first reptiles were split into different species 300 millions years ago, which marked the development of ancient birds. There are multiple anatomical features that resemble birds and reptiles, and they share characteristics such as laying amniotic eggs and having scales. In addition, modern DNA phylogenetic studies have corroborated that birds and reptiles share common ancestors.
