In the passage, the two highlighted portions play which of the following roles? A. The first states observation the accuracy of which is challenged in the passage; the second is part of the ground on which that challenge is based. B. The first states observations that, according to the passage, are incompatible with a certain hypothesis; the second is part of the grounds offered in support of a revision of that hypothesis. C. The first states observations that, according to the passage, can be reconciled with a certain hypothesis; the second describes a phenomenon that is factual basis of that reconciliation. D. The first presents a phenomenon, two competing explanations of which are considered in the passage; the second is the explanation of the phenomenon that the passage argues is correct. E. The first provides evidence against a position; the second is that position.