Sentence Correction (SC) | Re: The African crocodile, an amphibious reptile that preys on a variety

The African crocodile, an amphibious reptile that preys on a variety of animals,are one of the oldest animal species on our planet .
The african crocodile --> Singular noun
Check again with the modifier portion "an amphibious reptile...". Ok we need to correct this with singular verb.

A.are one of the oldest animal species on our planet ---> plural verb

B. is one of the oldest animal species on Earth ---> Correct

C. is the oldestEarth species ---> what is earth species??