The correct option is
A reptiles gave rise to birds
Fossils are the preserved remains or impressions of organisms that existed in a past geological age. Fossils are generally found in sedimentary rocks as they are formed by the accumulation and deposition of minerals and other inorganic materials on the buried carcasses of living creatures.
Evidence has suggested that birds evolved from the carnivorous dinosaur (reptile). It is evident from the characters of Archaeopteryx (a reptile), whose fossil was found. It is considered as a transitional fossil between reptiles and modern birds.
Organisms (fossils) showing intermediate conditions between ancestral forms and its corresponding descendants are known as Transitional fossils or 'Missing Links'.
For example, Archaeopteryx had jaws with teeth and a long bony tail like that of reptiles. However, it also had broad wings and feathers like birds. Archaeopteryx is a carnivorous (flesh eating) dinosaur not herbivorous, it used to feed on small reptiles, amphibians, mammals, and insects. So options a and c are incorrect.
Thus, it can be concluded that the reptiles gave rise to birds via transitional species like Archaeopteryx. Hence option b is correct and option d is incorrect.
Figure : Evolutionary tree of birds from reptiles