GMAT Sentence Correction (SC) | Re: The naked mole rat is unique because

The naked mole rat is unique because it can run as fast backwards as forwards, which is not known to exist in any other animal.
A. because it can run as fast backwards as forwards, which is not known to exist in any other animal
B. because they can run as fast backwards as forwards, which is not known to be the case with any other animal
C. since it can run equally efficiently backwards as forwards; this skill is not known to exist in any other animal
D. since it runs as well backwards