The correct option is B Archaeopteryx
Missing links or transitional species are those intermediate species in the line of evolution, that exhibit characteristics that were found in their immediate ancestral and descendant groups. These links thus, fill up the so-called gaps in the evolutionary record of species. For example, Archaeopteryx is a link, that was missing for a long time in the evolutionary record between reptiles and birds. It is today, known as a transitional species between the two groups - reptiles and birds. Archaeopteryx had jaws with teeth and a long bony tail like the dinosaurs, broad wings and feathers like birds, and skeletal features of both.