Answer:
d. by acknowledging that some people disagree with his position
Explanation:
Roberto addresses this new information "by acknowledging that some people disagree with his position"
Roberto cannot ignore the new source or call it foolish but can only acknowledge it and then finds better reasons to support his own claims above what the new information says.
I have been scientifically studying the traits and dispositions of the "lower animals" (so-called), and contrasting them with the traits and dispositions of man. I find the result humiliating to me. For it obliges me to renounce my allegiance to the Darwinian<span>theory of the Ascent of Man from the Lower Animals; since it now seems plain to me that the theory ought to be vacated in favor of a new and truer one, this new and truer one to be named the Descent of Man from the Higher Animals.</span>
