What percentage of carbon-14 will be left in fossil after it has decayed on 11,400 years

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands

i think the answer would be a. after sentence 14! i hope i at least a little