In the following question, a sentence is given with certain words in bold. Choose the pair/s of such words which need to be interchanged so as to make the sentence grammatically correct and meaningful.

Rather, it had to be (A) signifying as a structure of (B) variant possibilities, the arrangement of elements in a (C) analyzed chain, as a practice not 'expressing' the world but articulating it, (D) articulated upon it.