GMAT Reading Comprehension (RC) | Re: Milankovitch proposed inthe early twentieth century that the

Hi,

Can anyone please explain the Q2 - answer? Why it's option 'D', while i understood it should be as 'B'.
It's only mentioned that there are other factors which can play a role in assessing M's discovery, and no where mentioned that there are other discoveries as well to find the ice age. Thanks!

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