GMAT Sentence Correction (SC) | Re: While global temperatures have risen sharply over the last century, th

While global temperatures have risen sharply over the last century, they have only recently eclipsed the Medieval period, during which scientists theorize that a series of volcanic eruptions sent the earth into a period of historicwarmth.

A. they have only recently eclipsed the Medieval period, during which scientists theorize that a The scientist did not theorized during the medival period but they theorised about medival period tempratures.
B. they have only recently eclipsed those of the Medieval period,
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