GMAT Sentence Correction (SC) | Re: In the Amazon, the alignment

In the Amazon, the alignment of a fertile ecosystem andisolation from other ecologies during early geological epochs has given rise to a great diversity of species, which, in many genuses, outnumber those is other regions on earth by 100 to 1.

A) isolation from other ecologies during early geological epochs has given rise to a great diversity of species, which, in many genuses, outnumber

B) isolation from other ecologies during early geological epochs has given rise to a great diversity of