The correct answer is option A, that is, jaw or jawless fishes.
Agnatha refers to the superclass of jawless fish in the phylum Chordata, subphylum Vertebrata, comprising of both the extinct (conodonts and ostracoderms) and present (cyclostomes) species. It comprises the group of all vertebrates with jaws, that is, gnathostomes.
On the other hand, there are two categories of living fish with jaws. The Osteichthyes (the bony fish) and the Chondrichthyes (the cartilaginous fish). Both the categories of fish comprises of two pairs of lateral fins and a finned tail for impulsion in water.
