In the sentence, certain words are in bold and numbered from A to E, which are the possible pairs to be interchanged. Choose the pair(s) of words which need to be interchanged to make the sentence grammatically correct and meaningful. 

When, however, the human mind was (A) illumined by the torch-light of science, it came to understand that the Earth was but one of a (B) speck of stars (C) floating in (D) infinite space, a mere (E) myriad of dust.