GMAT Sentence Correction (SC) | Re: The Greek mathematician Archimedes is most famous for discovering that

I picked A, but I think each answer iswrong.

A. discovering that the quantities of water displaced by an immersed object have
quantities don't have volume rather water hasvolume.
B. his discovery that by immersing objects in water, they displace quantities of
pronoun "they" has noantecedent.
C. discovering that the quantities of water displaced by an immersed object has
quantities ... has violates S/V agreement.
D. discovering the quantities of water displaced by an immersed object of
...

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