GMAT Sentence Correction (SC) | Re: Until a few centuries ago, any large bones discovered in the

Until a few centuries ago, any large bones discovered in the fields or caves of Europe,now known to be large prehistoric animals, were usually assumed to be the remains of giants and were often displayed as curiosities in castles, palaces, town halls, churches, and monasteries.

A) now known to be large prehistoric animals, were usually assumed to be - "large bones" cannot "be" "large prehistoric animals"
B) presently known as from large prehistoric animals, were
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