Haikouichthys lanceolata is one of the oldest fossil chordates known. It shares with lampreys some specific features of the eye and eye muscles. From this, we can infer that Haikouichthys probably possessed _____.
A. vertebrae and jaws
B. a cranium and vertebrae, but no jaws or paired fins
C. a cranium but no vertebrae
D. segmental muscles but no cranium